1-Step 1: Preheat and Prep Begin by preheating your oven to 375°F (190°C). Line a 17×11 inch (43×28 cm) deep baking sheet with parchment paper and give it a quick spray with cooking spray. This sets the stage for even baking and easy removal later. Whisk together the flour, cocoa powder, baking powder, and salt in a bowl to mix the dry ingredients evenly.

2-Step 2: Beat the Wet Ingredients In a separate bowl, beat the eggs, sugar, and vanilla extract on medium-high speed for about 5 minutes. You’ll see the mixture turn thick, white, and triple in size it’s like magic happening right there. This step is crucial for that light, airy texture, so don’t rush it.

3-Step 3: Melt and Combine Melt the butter and semi-sweet chocolate together in a double boiler, stirring until smooth, then let it cool slightly. Gently fold this into the egg mixture, taking care not to deflate all that lovely air. Next, fold in the dry ingredients until just combined the batter should be rich and glossy.

4-Step 4: Bake and Cool Pour the batter into your prepared pan, tap it gently to remove any bubbles, and bake for 10-12 minutes. Check with a toothpick; it should come out clean when done. Let the cake cool in the pan for 5 minutes, then invert it onto a wire rack, remove the parchment, and cool completely. This cooling process helps the cake set without cracking.

5-Step 5: Make the Buttercream and Assemble Beat the softened butter and pistachio paste until fluffy, then add powdered sugar, heavy cream, and vanilla extract. Beat until smooth and spreadable it’s that creamy topping that takes these cakes over the top! Cut the cooled cake into 2-inch circles, pipe buttercream onto half of them, stack with the plain ones, and frost the tops. Sprinkle with chopped pistachios for a finishing touch.