Step 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 to ensure easy removal after baking.

Step 2: Mix the Dry Ingredients
In a large mixing bowl, sift or whisk together the flour, cocoa powder, sugar, baking powder, baking soda, and salt until thoroughly combined.

Step 3: Add the Wet Ingredients
In a separate bowl, beat together the eggs, milk, oil, and vanilla extract. Gradually add the wet mixture to the dry ingredients, mixing until smooth and no lumps remain.

Step 4: Incorporate the Hot Water
Slowly pour in the boiling water or hot coffee while gently stirring. The batter will be thin—this helps achieve a moist, tender cake with a deep chocolate flavor.

Step 5: Bake the Cake
Divide the batter evenly between the prepared pans. Smooth the tops with a spatula if needed. Bake for 30–35 minutes, or until a toothpick inserted into the center comes out clean or with a few moist crumbs. Let the cakes cool in their pans for 10 minutes before turning them out onto a wire rack to cool completely.

Step 6: Make the Chocolate Ganache (Optional)
Heat the heavy cream in a small saucepan over medium heat until it just begins to simmer—do not let it boil. Place the chocolate chips or chopped chocolate in a heatproof bowl and pour the hot cream over them. Let it sit undisturbed for 2–3 minutes, then whisk until smooth and glossy. Allow the ganache to cool slightly so it thickens enough for spreading.

Step 7: Assemble and Frost
Once the cake layers are completely cooled, place one on a serving plate. Spread a layer of ganache or your favorite frosting over the top. Place the second layer on top and frost the top and sides of the cake with the remaining ganache or frosting.