Step 1: Prepare the Cake Batter

1. Preheat the Oven: Preheat your oven to 350°F (175°C). Grease and flour two 9-inch round cake pans or line them with parchment paper for easy removal after baking.
2. Mix Dry Ingredients: In a large bowl, whisk together the all-purpose flour, sugar, cocoa powder, baking powder, baking soda, and salt. This will ensure that all the dry ingredients are well combined.
3. Add Wet Ingredients: In another bowl, whisk together the eggs, milk, vegetable oil, and vanilla extract. Stir until smooth and fully combined.
4. Combine Wet and Dry: Gradually add the wet ingredients to the dry ingredients, mixing gently with a spatula or electric mixer until just combined.
5. Add Boiling Water and Coffee: Pour in the boiling water (and coffee, if using) and mix until the batter is smooth and slightly runny. The liquid helps create a moist, tender cake.

Step 2: Bake the Cake

6. Pour the Batter into Pans: Divide the cake batter evenly between the two prepared pans. Smooth the tops with a spatula.
7. Bake: Bake the cakes in the preheated oven for 35-40 minutes, or until a toothpick inserted into the center of the cakes comes out clean. If the toothpick comes out with wet batter, bake for an additional 5 minutes and check again.
8. Cool the Cakes: Allow the cakes to cool in the pans for about 10 minutes before transferring them to a wire rack to cool completely.

Step 3: Prepare the Peanut Butter Frosting

9. Mix the Frosting: In a large mixing bowl, combine the softened butter and peanut butter. Use an electric mixer or whisk to beat them together until smooth and creamy.
10. Add Powdered Sugar: Gradually add the powdered sugar, one cup at a time, mixing well after each addition. Continue to beat until the frosting is smooth and fluffy.
11. Add Vanilla and Cream: Stir in the vanilla extract and heavy cream. If the frosting seems too thick, add a little more cream, one tablespoon at a time, until the desired consistency is achieved.

Step 4: Assemble the Cake

12. Frost the First Layer: Place one of the cooled cakes on a serving plate or cake stand. Spread a generous layer of peanut butter frosting on top, smoothing it out evenly.
13. Add the Second Cake Layer: Place the second cake layer on top of the frosted cake. Press gently to ensure it’s even.
14. Frost the Entire Cake: Spread the remaining peanut butter frosting over the top and sides of the cake. Smooth it out to cover the entire cake with a thick, creamy layer of frosting.

Step 5: Decorate and Serve

15. Optional Decoration: If desired, sprinkle chopped peanuts over the top of the cake for some added crunch. You can also drizzle melted chocolate ganache or sprinkle chocolate chips for extra indulgence.
16. Serve: Slice the cake into generous portions and serve it with a glass of milk or a cup of coffee. Enjoy the rich combination of chocolate and peanut butter in every bite!