Description

A rich and decadent Chocolate Peanut Butter Cake perfect for large gatherings. This recipe combines a moist chocolate cake with fluffy peanut butter frosting, topped with Reece’s Peanut Butter Cups and a drizzle of melted chocolate and peanut butter. Ideal for serving 20 to 25 people, it’s a crowd-pleasing dessert that balances sweetness with a touch of salt to enhance the flavors.

Ingredients

Scale

Dry Ingredients

1 3/4 cups plain / all purpose flour
3/4 cup unsweetened cocoa powder
1 1/2 tsp baking powder
1 1/2 tsp baking soda (bi-carb soda)
2 cups white sugar (or caster/superfine sugar)
1 tsp cooking / kosher salt

Wet Ingredients

2 large eggs
1 cup milk (low or full fat)
1/2 cup vegetable oil (or plain flavoured oil like canola, grapeseed, rapeseed, sunflower)
2 tsp vanilla extract
2 tsp instant coffee powder (optional)
1 cup boiling water

Frosting and Toppings

250g / 2 sticks unsalted butter, softened
4 cups (500 g) soft icing sugar / powdered sugar, sifted
1/2 cup (120 g) smooth peanut butter (spread, not pure)
1/4 tsp cooking/kosher salt
1 tbsp milk
1/2 cup chocolate chips or melts (US: semi sweet chips)
2 tbsp cream (thickened/heavy or pure, not low fat)
3 tbsp peanut butter, warmed to runny
120g / 4 oz mini Reece’s Peanut Butter Cups
10+ miniature Reece’s Peanut Butter Cups, halved
1/4 cup salted peanuts, finely chopped

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Instructions

Preheat and Prepare Pan: Preheat the oven to 180°C (350°F) or 160°C for fan-forced ovens. Grease a 23 x 33 cm (9 x 13 inch) metal cake pan with butter, then line it with baking paper with an overhang to make it easy to lift out after baking. For round cakes, refer to notes for size adjustments.
Mix Dry Ingredients: In a large bowl, sift together the flour, cocoa powder, baking powder, baking soda, sugar, and salt to combine evenly.
Add Wet Ingredients: Add eggs, milk, vegetable oil, vanilla extract, and instant coffee powder (if using) to the dry ingredients. Mix well until smooth and fully combined.
Incorporate Boiling Water: Carefully pour in the boiling water and stir until the batter is smooth and thin. This step enhances the chocolate flavor (‘blooms’ the cocoa).
Bake the Cake: Pour the batter into the prepared cake pan. Bake in the preheated oven for 45 minutes or until a toothpick inserted in the center comes out clean. Remove from oven and allow the cake to cool completely in the pan on a wire rack.
Prepare Frosting: Beat the softened unsalted butter until creamy. Gradually add the sifted icing sugar, followed by the smooth peanut butter, salt, and 1 tbsp milk. Continue beating until the frosting is fluffy and well combined.
Make Chocolate Ganache Drizzle: In a small saucepan, gently melt the chocolate chips with the cream over low heat, stirring continuously until smooth. Remove from heat and stir in 3 tbsp warmed peanut butter until fully combined.
Assemble the Cake: Remove the cooled cake from the pan using the paper overhang. Spread the peanut butter frosting evenly over the top of the cake.
Decorate: Arrange the mini Reece’s Peanut Butter Cups over the frosted cake. Drizzle the peanut butter chocolate ganache over the top. Finish by sprinkling the finely chopped salted peanuts and halved miniature Reece’s Peanut Butter Cups.
Serve: Slice into 20 to 25 portions and serve. The cake is rich, so small slices are recommended for best enjoyment.

Notes

Recipe VIDEO available for step-by-step visual guidance.
This cake is wonderfully rich and perfect for feeding a large crowd—serves approximately 20 to 25 people, up to 30 with smaller slices.
The unsweetened cocoa powder combines with boiling water to intensify the chocolate flavor by blooming the cocoa.
For round pans, adjust size to approximately two 23cm (9 inch) round cake pans.
The frosting includes a touch of salt to balance the sweetness and enhance the peanut butter flavor.
The instant coffee powder is optional but helps deepen the chocolate notes.

Nutrition

Serving Size: 1 slice (approximate)
Calories: 395 kcal
Sugar: 41 g
Sodium: 258 mg
Fat: 21 g
Saturated Fat: 8 g
Unsaturated Fat: 11 g
Trans Fat: 0.3 g
Carbohydrates: 51 g
Fiber: 2 g
Protein: 5 g
Cholesterol: 38 mg