Let milk, butter, and eggs come to room temperature
In a large bowl, sift together flour, cocoa powder, baking powder, sugar, and a pinch of salt
Add eggs, butter, vegetable oil, milk, and vanilla extract. Mix on low speed for 2–3 minutes
Line an 8-inch springform pan with parchment paper, grease it with butter, and pour in the batter
Bake at 310°F (155°C) for about 60–70 minutes
Use a toothpick to test doneness — if it comes out clean, it's ready. If not, continue baking and check every 5 minutes
Let the cake cool in the pan for 10 minutes, then transfer to a cooling rack
Wrap in plastic wrap and chill in the fridge for 40–60 minutes (or ideally a few hours or overnight)
Beat mascarpone with powdered sugar until creamy
In a separate bowl, whip heavy cream to soft peaks, then fold it into the mascarpone mixture
Cut off the top of the cake and slice it in half horizontally
Spread the cream over the bottom layer, then place the second layer on top
Heat heavy cream (do not boil), pour it over chopped chocolate, let sit for a minute, then whisk until smooth
Pour ganache over the cake and smooth it out
