1. Make the Chocolate Cake Layers:

Preheat oven to 350°F (176°C). Prepare three 8-inch round cake pans with non-stick baking spray, line bottoms with parchment paper, and spray parchment.

Add the flour, sugar, cocoa, baking soda, baking powder, and salt to a large mixer bowl (or large bowl) and combine well (whisk or use mixer on low).

In a separate medium bowl, combine the milk, vegetable oil, vanilla extract, and eggs. Whisk together.

Add the wet ingredients to the dry ingredients in the mixer bowl. Beat on low speed, then medium speed until well combined. Scrape down the sides.

With the mixer on low speed, slowly add the hot water (or hot coffee) to the batter. Mix until well combined. The batter will be thin.

Divide the batter evenly between the three prepared cake pans.

Bake for 22-25 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs.

Cool cakes in the pans for 2-3 minutes, then carefully invert them onto cooling racks, remove parchment, and let cool completely.

2. Make the Peanut Butter Frosting:

Combine the room temperature salted butter and creamy peanut butter in a large mixer bowl (use paddle attachment). Mix on medium speed until well combined and smooth.

Add about half (approx. 4.5 cups) of the sifted powdered sugar. Mix on low speed until incorporated, then increase speed and mix until smooth.

Add 3 tablespoons of water or milk. Mix on low until combined, then medium until smooth.

Add the remaining half of the sifted powdered sugar. Mix on low until incorporated, then medium until smooth.

Add the remaining 3-4 tablespoons of water or milk, one tablespoon at a time, mixing until the frosting is smooth and reaches a good spreading consistency. Be careful not to make it too thin.

3. Assemble the Cake Layers:

Once cakes are completely cool, use a large serrated knife to level the tops, making them flat.

Place the first cake layer on a serving plate or cardboard cake circle. Top with about 1 cup of peanut butter frosting. Smooth the frosting into an even layer.

Sprinkle about half (3 chopped Reese’s) of the chopped Reese’s evenly over the frosting. Gently press them into the frosting.

Spread a very small amount of additional frosting over the Reese’s pieces to help the next layer adhere (“glue”).

Add the second cake layer. Top with another 1 cup of frosting, smooth evenly.

Add the remaining half (3 chopped Reese’s) of the chopped Reese’s over the second frosting layer, press gently. Add another thin layer of “glue” frosting.

Add the final cake layer to the top, placing it upside down for a perfectly flat top surface.

4. Crumb Coat and Chill:

Use an offset spatula to apply a thin layer of peanut butter frosting over the entire cake (top and sides), smoothing it out to trap any loose crumbs. This is the “crumb coat.” It doesn’t need to be thick or perfect.

Chill the crumb-coated cake in the refrigerator for at least 30 minutes to firm up.

5. Final Frosting & Optional Stripes:

Apply the remaining peanut butter frosting to the sides and top of the chilled cake. Use an offset spatula and potentially a bench scraper for smooth sides. (Follow linked tutorial if desired).

(Optional Stripes): The recipe mentions creating stripes with an offset spatula – this involves gently pressing the tip or edge of the spatula into the frosting and rotating the cake (on a turntable) to create horizontal lines/ridges. See video reference in original recipe for visual guide.

Set the cake aside (briefly chilling again helps before ganache).

6. Make and Apply Ganache:

Put the semi-sweet chocolate chips in a heatproof bowl.

Microwave the heavy whipping cream until it just begins to boil (watch carefully!).

Pour the hot cream over the chocolate chips. Let sit undisturbed for 2-3 minutes.

Whisk the mixture gently until the ganache is completely smooth and glossy.

Let the ganache cool slightly until it’s thickened but still pourable (test consistency for dripping).

Using a squeeze bottle or a spoon, carefully drizzle the chocolate ganache around the top edge of the cake, allowing it to drip down the sides naturally.

Fill in the center of the top of the cake with the remaining ganache and smooth it carefully with a small offset spatula.

7. Final Decorations:

Allow the ganache to set slightly, about 10 minutes (at room temp or briefly in fridge).

Transfer some remaining peanut butter frosting (if any reserved, or make a bit extra) to a piping bag fitted with a large closed star tip (like Ateco 844 or Wilton 1M/2D).

Pipe decorative swirls or dollops around the top edge of the cake, on top of the ganache.

Top the swirls with Reese’s Peanut Butter Cups cut in half. Sprinkle Reese’s crumbles over the center or around the base.

8. Chill and Serve:

Refrigerate the finished cake until ready to serve (at least 30 mins for ganache to fully set).

For best flavor and texture, let the cake sit at room temperature for about 20-30 minutes before slicing and serving. Store leftovers covered in the refrigerator.