Printed on the back of Hershey’s Cocoa cans since the 1940s, this one-bowl layer cake relies on vegetable oil, buttermilk, and a full cup of boiling water. The batter looks alarmingly thin, but that thinness is what produces the moist, tender crumb the recipe is known for.
What follows covers every ingredient’s role, the science behind the boiling-water step, pan adaptations, frosting technique, and troubleshooting for the most common failures.
A Recipe That Hasn’t Changed Since the 1940s
During World War II, butter rationing forced American home bakers to find alternatives. Hershey’s responded by printing a chocolate cake recipe directly on the back of their cocoa cans, one built around vegetable oil instead of butter. That single decision created a cake that stays moist even after refrigeration, and the formula has remained virtually untouched for over 80 years.
The recipe spread through church bake sales, county fairs, and handwritten index cards rather than television advertising. By the 1970s, it had earned a reputation as the most reliable homemade chocolate cake in the country, passed between neighbors the way sourdough starters are today.
Why the One-Bowl Method Endured
Accessibility is the reason. No stand mixer, no creaming step, no separated eggs. A wooden spoon and a large bowl are all the equipment required. That simplicity made it possible during wartime shortages, and it remains the reason this recipe gets pulled out for birthday emergencies and last-minute potlucks decades later.
The original recipe card from the 1940s lists the exact same proportions found on current Hershey’s Cocoa cans. The only change over the decades has been graphic design, not ingredients.
The Full Ingredient List and What Each One Does
Understanding why each ingredient earns its place prevents the substitutions that quietly ruin the result. Here is the complete dry and wet lineup with the role each one plays:
- All-purpose flour (1¾ cups): Provides structure without the toughness that bread flour would create. The moderate protein content keeps the crumb tender.
- Granulated sugar (2 cups): Sweetens, but also retains moisture and interferes with gluten formation for a softer texture.
- Hershey’s cocoa powder (¾ cup): The flavor backbone. Natural, non-alkalized cocoa is specified for a reason covered in the comparison section below.
- Baking soda (1½ teaspoons): Reacts with the acid in buttermilk to produce carbon dioxide bubbles that lift the batter.
- Baking powder (1½ teaspoons): Provides a second rise during baking, ensuring the layers don’t collapse after the initial soda reaction exhausts itself.
- Salt (1 teaspoon): Sharpens chocolate flavor and balances sweetness without making the cake taste salty.
- Buttermilk (1 cup): Its lactic acid activates the baking soda and adds a subtle tang that deepens the chocolate character.
- Vegetable oil (½ cup): Stays liquid at room temperature and when chilled, which is why this cake remains moist straight from the refrigerator. Butter solidifies and firms the crumb.
- Eggs (2 large): Add structure and richness through their proteins and emulsifiers without weighing down the delicate crumb.
- Boiling water (1 cup): The final and most misunderstood addition. Its purpose goes far beyond simple hydration.
Each ingredient exists in a specific ratio to the others. Swapping one without adjusting the rest throws off the chemistry. That balance is what separates this recipe from a generic chocolate cake formula.
Why Boiling Water and Thin Batter Are the Point
The step that sends most first-time bakers into a panic is the one doing the most work. Pouring a full cup of boiling water into the batter is not a typo or a mistake. It is the single most important technique in the entire process.
How Boiling Water Blooms Cocoa
Cocoa powder contains fat-soluble flavor compounds that remain locked and muted when mixed with cold or room-temperature liquid. Boiling water dissolves those compounds and releases them into the batter, intensifying the chocolate flavor in a way that no amount of extra cocoa can replicate. This process, called blooming, is the same reason some brownie recipes call for hot coffee or melted chocolate.
The heat also partially gelatinizes the starch in the flour, which helps the crumb hold more moisture without becoming gummy. That combination of deeper flavor and better moisture retention is what gives this cake its signature richness.
The Batter Should Look Wrong
After the boiling water goes in, the batter will resemble thin crepe batter or even a pourable pancake mix. This is correct and intentional. Resist the urge to add more flour. The high liquid ratio creates steam during baking, and that steam produces the open, tender crumb the cake is known for.
That steam-driven crumb depends heavily on which type of cocoa you reach for.
Stir only until the water is incorporated. Over-mixing at this stage develops gluten in the flour and turns the crumb tough and chewy instead of soft and tender. Ten to fifteen gentle strokes with a spoon is enough.
Natural Cocoa Versus Dutch-Processed in This Recipe
The type of cocoa powder you reach for determines whether the cake rises properly or collapses into a dense, flat disc. This is the single most common substitution error with this recipe.
| Factor | Natural Cocoa (Required) | Dutch-Processed Cocoa |
|---|---|---|
| Acidity | Acidic (pH around 5.5) | Neutralized (pH around 7) |
| Reaction with baking soda | Produces CO₂ for lift | No acid reaction, minimal lift |
| Resulting texture | Light, open crumb with good rise | Dense, flat, potentially gummy |
| Color in this recipe | Deep reddish-brown | Darker but less vibrant |
| Flavor intensity | Bright, complex chocolate notes | Milder, smoother, less acidic |
Hershey’s regular cocoa is natural and non-alkalized, which is exactly what the recipe was developed around. The acid in the cocoa works together with the buttermilk and baking soda to create the full leavening system. Remove that acid by using Dutch-processed cocoa, and the baking soda has nothing to react with.
Adapting for Dutch-Processed Cocoa
Substitutions are possible but require adjustments. Replace the baking soda entirely with baking powder (use 2 teaspoons) and add one teaspoon of white vinegar or lemon juice to restore the acid the recipe depends on. The result will still be a good cake, but the texture and flavor will differ slightly from the original formula. Hershey’s Special Dark Cocoa is a blend of natural and Dutch-processed cocoa, so it sits between the two options and works acceptably without modification.
Step-by-Step Baking Instructions With Visual Cues
Preheat your oven to 350°F before mixing anything. The batter comes together quickly, and having the oven ready prevents it from sitting while the heat climbs.
- Whisk the dry ingredients: Combine flour, sugar, cocoa, baking soda, baking powder, and salt in one large bowl. Whisk until no streaks of cocoa remain. This distributes the leavening evenly so the cake rises uniformly.
- Add the wet ingredients: Crack in the eggs, pour in the buttermilk, oil, and vanilla. Stir with a wooden spoon or sturdy spatula until smooth. The batter will be thick and glossy at this stage.
- Pour in the boiling water: Add it all at once. Stir gently, no more than 15 strokes. The batter will thin dramatically and look almost watery. This is the correct consistency.
- Divide into pans: Pour evenly between two greased and floured 9-inch round pans, or use a single 9×13 sheet pan. For round pans, lining the bottoms with parchment paper guarantees clean release.
- Bake at 350°F: Round layers need 30 to 35 minutes. The center should spring back when pressed lightly with a fingertip, and a toothpick inserted near the middle should show a few moist crumbs, not wet batter.
- Cool properly: Let the layers rest in their pans for exactly 10 minutes, then turn them out onto a wire rack. Cooling completely in the pan traps steam and makes the bottom soggy.
The visual cues matter more than the timer. Oven temperatures vary by as much as 25°F from their dial setting, so checking at the 28-minute mark saves you from overbaking. A cake pulled at the right moment will have edges that just begin to separate from the pan walls.
Once the layers are cool enough to handle, the frosting becomes the next variable to get right.
The Chocolate Buttercream Frosting That Pairs With It
Five ingredients,butter, cocoa powder, powdered sugar, milk, and vanilla,make up the simple chocolate buttercream that accompanies the original cocoa can recipe. It takes about eight minutes to make and pairs with the cake’s deep chocolate flavor without competing with it.
Building the Right Consistency
Beat ½ cup of softened butter until it turns pale and fluffy, about two minutes with a hand mixer. Sift in ⅔ cup of cocoa powder and 3 cups of powdered sugar alternately with ⅓ cup of milk, beating on low after each addition. The milk quantity is where most problems start. Add it one tablespoon at a time. Humidity, butter temperature, and even the brand of powdered sugar affect how much liquid the frosting absorbs.
The target consistency should hold a soft peak when you lift the beater and spread smoothly without tearing the crumb. Too stiff and it drags crumbs into the frosting. Too thin and it slides off the layers.
Frosting Temperature Rules
The cake layers must be completely cool before frosting touches them. Even slight warmth melts the butter in the frosting, causing the layers to slide apart and the filling to squeeze out the sides. A good test: press the center of a layer with your palm. It should feel no warmer than the room around it. For extra security, chill the layers in the refrigerator for 30 minutes before assembling.
Troubleshooting, Adaptations, and Storage
Most failures with this recipe trace back to one of three causes: incorrect oven temperature, wrong cocoa type, or overbaking. The table below maps specific symptoms to their fixes.
| Symptom | Likely Cause | Fix |
|---|---|---|
| Sunken center | Oven too low or door opened before 25 minutes | Verify temperature with a standalone oven thermometer; keep the door closed until the minimum bake time |
| Dry, crumbly texture | Overbaked by even 3 to 5 minutes | Pull when a toothpick shows moist crumbs, not clean; check at 28 minutes |
| Gummy or dense crumb | Too much flour from scooping the measuring cup directly into the bag | Spoon flour into the cup and level with a knife, or weigh 220 grams per cup |
| Flat layers with no dome | Dutch-processed cocoa replaced natural cocoa | Use natural cocoa or add 1 teaspoon vinegar and swap soda for baking powder |
| Frosting slides off layers | Cake still warm when frosted | Cool completely, then chill 30 minutes before assembling |
Adapting the Recipe for Different Pans
The same batter works across several formats with adjusted bake times:
- Cupcakes: Fill liners two-thirds full. Bake 18 to 22 minutes at 350°F. Yields 24 to 30 cupcakes.
- 9×13 sheet pan: Bake 35 to 40 minutes. No need to divide the batter. Cool completely in the pan before frosting.
- Bundt pan: Grease every crevice thoroughly with butter and flour. Bake 50 to 60 minutes. Cool 15 minutes before inverting onto a plate.
Storage and Make-Ahead Timing
The oil-based crumb keeps this cake moist longer than butter-based alternatives. At room temperature, frosted layers stay fresh for two days under a cake dome or inverted bowl. Refrigerated, the cake holds up to five days without drying out, which is rare for a homemade layer cake. For longer storage, wrap unfrosted layers tightly in plastic wrap and freeze for up to three months. Thaw at room temperature for two hours before frosting.
One detail worth knowing: the flavor actually deepens overnight. The cocoa compounds continue to develop as the cake rests, so a cake baked the day before serving tastes richer than one served the same afternoon.
Final Thoughts
Boiling water, thin batter, oil instead of butter. Every unusual element in this recipe serves a specific chemical purpose, and understanding those purposes is what separates a good result from a great one. Trust the process, use natural cocoa, pull the cake at the right moment, and you will produce a layer cake that rivals anything from a bakery case, using nothing more than a spoon and a single bowl.
FAQ
What is the official Hershey’s chocolate cake recipe?
Since the 1940s, the back of every Hershey’s Cocoa can has listed 1¾ cups all-purpose flour, 2 cups sugar, ¾ cup cocoa, 1½ teaspoons each of baking soda and baking powder, 1 teaspoon salt, 2 eggs, 1 cup buttermilk, ½ cup vegetable oil, 2 teaspoons vanilla, and 1 cup boiling water. Mix dry ingredients, add wet, stir in boiling water last, then bake at 350°F for 30 to 35 minutes in two 9-inch round pans.
What is the secret to a moist Hershey’s chocolate cake?
Vegetable oil is the primary factor because it stays liquid when cooled, unlike butter which solidifies. The boiling water step also contributes by gelatinizing starch and creating steam during baking, which produces an open, moisture-retaining crumb structure.
Can I use Hershey’s Special Dark Cocoa instead of regular cocoa?
Yes. Special Dark is a blend of natural and Dutch-processed cocoa, so it retains enough acidity to react with the baking soda. The cake will be slightly darker and milder in flavor but will rise and bake normally without any adjustments.
Why does the recipe call for boiling water?
Boiling water blooms the cocoa powder by dissolving fat-soluble flavor compounds that cold liquid cannot release. It also partially gelatinizes the flour starch, helping the crumb retain more moisture. The result is a deeper chocolate flavor and a softer texture than cold water would produce.
Can I substitute buttermilk in the Hershey’s chocolate cake recipe?
Yes. Mix 1 tablespoon of white vinegar or lemon juice into 1 cup of whole milk and let it sit for five minutes until it curdles slightly. This mimics the acidity that activates the baking soda. The texture will be nearly identical, though the flavor loses a faint tang that real buttermilk provides.
How do I make the chocolate buttercream frosting for Hershey’s cake?
Beat ½ cup softened butter until pale, about two minutes. Alternately sift in ⅔ cup cocoa powder and 3 cups powdered sugar with ⅓ cup milk, beating on low after each addition. Add milk one tablespoon at a time until the frosting holds a soft peak and spreads without tearing the crumb.
