
Line a cake pan with parchment paper. Preheat the oven to 180°C / 356°F. In a bowl, whisk together the ground almonds, flour, baking powder, and cocoa powder until evenly combined.

Cut the unsalted butter and milk chocolate into small pieces and place them in a heatproof bowl. Set the bowl over warm water at about 50°C / 122°F, let it sit briefly, then stir until smooth. Set aside to cool to 30°C / 86°F or lower.



In a large bowl, lightly beat the eggs until smooth. Add the granulated sugar and whisk for about 2 minutes, until the sugar begins to dissolve and the mixture looks slightly lighter.



Sift the dry ingredients into the egg mixture in three additions. Mix the first addition firmly until incorporated, then fold in the second and third additions more gently to keep the batter light.



Add the room-temperature milk and stir gently until the batter is smooth. Pour in the cooled chocolate-butter mixture and mix until fully combined, then continue stirring for about 1 minute for an even texture.



Pour the batter into the prepared pan and smooth the top. Reduce the oven temperature to 160°C / 320°F and bake for about 40 minutes, or until the center springs back lightly and a tester comes out with a few moist crumbs.



Let the cake cool in the pan for 20 minutes, then remove it carefully. While it is still slightly warm, wrap it in plastic wrap to help retain moisture, then cool completely.


To make the ganache, finely chop the milk chocolate. Heat the heavy cream until just before boiling, pour it over the chocolate, and let it stand for 30 seconds. Stir until glossy and smooth.
Chill the ganache until it thickens enough to drizzle or spread. Spoon it over the cooled cake before serving.