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Chocolate Peanut Butter Cake for a Crowd
5 from 40 votes

Chocolate Peanut Butter Cake for a Crowd

The Chocolate Peanut Butter Cake for a Crowd combines cocoa, coffee, and peanut butter flavors in a large, moist cake. The batter uses both baking powder and baking soda for a tender crumb, and instant coffee enhances the chocolate taste. A rich peanut butter buttercream frosting with icing sugar and salt finishes the cake. Optional toppings include chocolate chips, cream, peanut butter drizzle, and chopped peanut butter cups for added texture and flavor contrast.

Prep Time
30 mins
Cook Time
45 mins
Cooling
2 hrs
Total Time
3 hrs 15 mins
Servings: 20 - 25 people
Calories: 395 kcal
Course: Dessert, Cake
Cuisine: American

Ingredients

  • 1 3/4 cups flour , plain / all purpose
  • 3/4 cup cocoa powder , unsweetened (Note 1)
  • 1 1/2 tsp baking powder
  • 1 1/2 tsp baking soda (bi-carb soda) (Note 2)
  • 2 cups white sugar or caster/superfine sugar
  • 1 tsp kosher salt yes, really!, cooking salt
  • 2 egg ~55-65g / 2 oz each - see here for size info, large
  • 1 cup milk (low or full fat)
  • 1/2 cup vegetable oil , or other plain flavoured oil like canola, grapeseed, rapeseed, sunflower
  • 2 tsp vanilla extract
  • 2 tsp instant coffee OPTIONAL (Note 3, powder
  • 1 cup water makes the chocolate flavour "bloom", boiling
Peanut Butter Buttercream Frosting
  • 250g / 2 sticks butter softened, unsalted
  • 4 cups (500 g) icing sugar sifted (Note 4, soft, aka powdered sugar
  • 1/2 cup (120 g) peanut butter spread, not pure) (Note 5, smooth
  • 1/4 tsp kosher salt cooking salt
  • 1 tbsp milk
Toppings (optional, recommended)
  • 1/2 cup chocolate chips US: semi sweet chips, or melts
  • 2 tbsp cream (thickened/heavy or pure, not low fat)
  • 3 tbsp peanut butter , warmed in microwave to make it runny
  • 120g / 4 oz Reese's peanut butter cups mini
  • 10+ Reese's peanut butter cups halved, miniature
  • 1/4 cup peanuts finely chopped, salted

Instructions

    Cup of Yum
  1. Preheat oven to 180C°/350°F (160°C fan).
  2. Grease a 23 x 33cm / 9 x 13" metal cake pan with butter. Then line with paper with overhang, to make it easier to lift out. (For round pans, see Note 4).
Batter:
  1. Dry ingredients - Sift flour, cocoa, baking powder and baking soda into a large bowl. Add Sugar and salt. Whisk briefly to combine.
  2. Wet ingredients - Add eggs, milk, oil and vanilla. Whisk well to combine until lump free - about 30 seconds.
  3. Boiling water - Add the coffee powder then the boiling water. Whisk to incorporate. The batter is VERY thin (see video). Pour batter into the cake pan.
Bake:
  1. Bake for 45 minutes or until a wooden skewer inserted into the centre comes out clean.
  2. Cool for 10 minutes, then fully cool on a wire rack before frosting (~2 hours).
Peanut butter buttercream frosting
  1. Beat butter for 3 minutes on high until soft and fluffy, using a stand mixer with the paddle attachment or handheld beater.
  2. Icing sugar - Add icing sugar in 3 lots. Beat it in, starting on low speed then increasing the speed (to avoid a snow storm). Once incorporated, add more icing sugar and repeat.
  3. Beat 3 minutes – Once the icing sugar has all been added, added the peanut butter, salt and milk. Beat on high speed for 3 minutes to make it really nice and fluffy. Ready to use!
Decorating
  1. Chocolate drizzle - Place the chocolate and cream in a small bowl. Microwave in 15 second increments on high, stirring in between, until smooth. Cool for 10 minutes before using.
  2. Frost - Spread all the frosting across the surface of the cake, from edge to edge.
  3. Decorate - Drizzle the top randomly with half the chocolate drizzle and melted peanut butter. Sprinkle with the peanut butter cups. Drizzle with remaining chocolate and peanut butter and sprinkle with the peanuts.
  4. Serve immediately! Cut into pieces as large (or small 😢) as you want. Refrigerate leftovers for 5 days though always bring to room temperature (because the frosting goes hard when cold).

Notes

  • Using instant coffee powder enhances the chocolate flavor without adding coffee taste.
  • Use softened unsalted butter and sifted icing sugar for a smooth and fluffy peanut butter frosting.
  • If using natural unsweetened peanut butter, reduce quantity to avoid overly loose frosting.
  • Cool the cake completely on a wire rack before applying frosting to ensure easier spreading.
  • For multiple layers, adjust baking time and pan sizes accordingly; the batter is thin—use liners to prevent leaks in round pans.
  • The frosted cake can be refrigerated for up to 5 days; bring to room temperature before serving.

Nutrition Information

Calories 395cal (20%) Carbohydrates 51g (17%) Protein 5g (10%) Fat 21g (32%) Saturated Fat 8g (40%) Polyunsaturated Fat 3g (18%) Monounsaturated Fat 8g (40%) Trans Fat 0.3g (15%) Cholesterol 38mg (13%) Sodium 258mg (11%) Potassium 177mg (4%) Fiber 2g (8%) Sugar 41g (82%) Vitamin A 308IU (6%) Vitamin C 0.03mg (0%) Calcium 45mg (5%) Iron 1mg (6%)

Nutrition Facts

Serving: 20 - 25 people

Amount Per Serving

Calories 395

% Daily Value*

Calories 395cal 20%
Carbohydrates 51g 17%
Protein 5g 10%
Fat 21g 32%
Saturated Fat 8g 40%
Polyunsaturated Fat 3g 18%
Monounsaturated Fat 8g 40%
Trans Fat 0.3g 15%
Cholesterol 38mg 13%
Sodium 258mg 11%
Potassium 177mg 4%
Fiber 2g 8%
Sugar 41g 82%
Vitamin A 308IU 6%
Vitamin C 0.03mg 0%
Calcium 45mg 5%
Iron 1mg 6%

* Percent Daily Values are based on a 2,000 calorie diet.