Step 1: Preheat Oven and Prepare Pans : Preheat oven to 350°F (175°C). Grease and line two 9-inch round cake pans with parchment paper.

Step 2: Mix Dry Ingredients : In a large bowl, sift together flour, cocoa powder, baking powder, baking soda, salt, and sugar.

Step 3: Combine Wet Ingredients : In another bowl, whisk together eggs, milk, oil, and vanilla extract. Stir the wet ingredients into the dry ingredients until smooth.

Step 4: Add Boiling Water : Dissolve instant coffee granules in boiling water (if using). Gradually stir the hot water into the batter — batter will be thin, but that’s normal.

Step 5: Bake the Cake : Divide batter evenly between the prepared pans. Bake for 35–40 minutes, or until a toothpick inserted in the center comes out clean or with a few moist crumbs. Let cakes cool in pans for 10 minutes, then transfer to wire racks to cool completely.

Step 6: Prepare the Chocolate Ganache : Heat heavy cream in a small saucepan until just simmering. Pour over chopped chocolate in a heatproof bowl and let sit for 2–3 minutes. Stir gently until smooth and glossy. Add butter for extra shine if desired. Allow ganache to cool slightly to thicken before pouring over cake.

Step 7: Assemble the Cake : Place one cake layer on a serving plate. Pour a small amount of ganache on top if you like extra chocolate between layers. Place the second cake layer on top. Pour remaining ganache over the top, letting it drip down the sides. Smooth with a spatula or let it naturally drip for a rustic look.

Step 8: Serve : Allow ganache to set slightly (10–15 minutes) before slicing. Slice with a sharp knife for clean edges. Serve at room temperature for the best fudgy texture.