Preheat your oven to 350°F (175°C) and grease two 9-inch round cake pans.
In a large mixing bowl, combine flour, cocoa powder, sugar, baking powder, baking soda, and salt.
In another bowl, whisk together the eggs, milk, and melted butter until well combined.
Pour the wet ingredients into the dry ingredients, mixing until just combined.
Fold in the chopped dark chocolate, ensuring it is evenly distributed throughout the batter.
Divide the batter evenly between the two prepared pans and smooth the tops.
Bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean.
Allow the cakes to cool in the pans for about 10 minutes, then turn them out onto wire racks to cool completely.
Prepare the chocolate ganache by heating the remaining cream and pouring it over the chopped dark chocolate. Stir until smooth and let it cool slightly.
Once the cakes are completely cool, place one layer on a serving plate, spread ganache on top, and then place the second layer on top. Cover the entire cake in the remaining ganache.
Let the ganache set for about 30 minutes before slicing and serving.
