Black Magic Snack Cake with Cocoa Frosting
- Prep
- 15 min
- Cook
- 38 min
- Yield
- 24 servings
- Level
- medium
- Cuisine
- American
A classic sheet cake with deep chocolate flavor from cocoa and strong coffee. The thin batter creates a tender crumb while the creamy cocoa frosting adds richness. Serve at potlucks, bake sales, or casual gatherings. This version uses coffee to amplify chocolate notes without adding coffee flavor.
No ratings yet — be the first
Ingredients
- 2 cup sugar, granulated
- 1 ¾ cup all-purpose flour, or cake flour
- ¾ cup unsweetened cocoa powder, sifted
- 2 teaspoon baking soda, leveled
- 1 teaspoon baking powder, leveled
- 1 teaspoon salt, fine
- 2 eggs, room temperature2 flax eggs (2 tablespoons ground flaxseed + 6 tablespoons water, sit 15 minutes)1:1vegan
medium
Full guide → - 1 cup buttermilk, room temperature
- 1 cup strong black coffee, brewed, cooled slightly
- ½ cup vegetable oil, neutral
- 1 teaspoon vanilla extract, pure
- ⅝ cup unsweetened cocoa powder, for frosting
- ½ pound butter, unsalted, softened
- 3 cup powdered sugar, sifted
- ⅓ cup milk, whole or 2%
Method
10 steps- 1
Heat oven to 350°F and grease and flour a 13 x 9 x 2-inch baking pan.
- 2
Whisk together sugar, flour, cocoa, baking soda, baking powder, and salt in a large bowl.
- 3
Add eggs, buttermilk, coffee, oil, and vanilla; beat on medium speed for 2 minutes until thin batter forms.
- 4
Pour batter evenly into prepared pan.
- 5
Bake for 35 to 40 minutes until a wooden pick inserted in the center comes out clean.
- 6
Cool on a wire rack.
- 7
For frosting, melt butter and stir in cocoa powder.
- 8
Alternately add powdered sugar and milk, beating until spreading consistency is reached.
- 9
Add additional milk as needed and stir in vanilla.
- 10
Frost the cooled cake.
Tips
Use strong brewed coffee at room temperature to enhance chocolate without making the cake taste like coffee; instant espresso powder also works.
Beat the batter for the full 2 minutes to develop structure; the thin consistency is intentional and yields a moist crumb.
Sift cocoa and powdered sugar separately to eliminate lumps in both batter and frosting for smooth texture.
Good to Know
Cover and refrigerate up to 4 days. Store at room temperature in airtight container up to 2 days.
Bake cake 1 day ahead; frost just before serving or up to 4 hours ahead. Frosting sets slightly when chilled.
Serve at room temperature with coffee, milk, or ice cream. Cut into 12-16 squares.
Common Mistakes
Do not skip beating the batter for 2 minutes to avoid a dense, flat cake.
Do not frost the cake while warm to avoid frosting melting and sliding off.
Do not over-beat the frosting after reaching spreading consistency to avoid breaking the emulsion.
Substitutions
Dairy-Free Swaps
none
Vegan Options
medium
Full guide →General Alternatives
FAQ
Can I make this ahead for a party?
Yes. Bake the cake up to 1 day ahead and store covered at room temperature. Make frosting and frost 4-6 hours before serving, or frost just before serving and refrigerate.
What if my frosting is too thick to spread?
Add milk 1 tablespoon at a time while beating until you reach spreading consistency. If too thin, add sifted powdered sugar gradually.
Can I freeze this cake?
Yes. Wrap unfrosted cake tightly in plastic wrap and foil; freeze up to 3 months. Thaw at room temperature before frosting. Frosted cake freezes up to 1 month.