01 - Preheat oven to 350°F. Grease and line two 9-inch round cake pans with parchment paper.
02 - Sift flour, cocoa powder, sugar, baking powder, baking soda, and salt into a large bowl.
03 - Incorporate eggs, milk, oil, and vanilla extract. Beat on medium speed for 2 minutes until fully combined.
04 - Stir in boiling water carefully; batter will be thin.
05 - Pour batter evenly into prepared pans. Bake for 30–35 minutes, or until a toothpick inserted in the center comes out clean.
06 - Allow cakes to cool in pans for 10 minutes, then transfer to wire racks to cool completely.
07 - Place chopped chocolate in a heatproof bowl. Heat cream until just simmering, pour over chocolate. Let rest 2–3 minutes, add butter, and stir until smooth and glossy. Cool until thickened but pourable.
08 - Place one cake layer on serving plate, spread ganache evenly over top. Add second layer, then cover top and sides with remaining ganache.
09 - Let cake rest at room temperature or refrigerate for firmer ganache before slicing.