Preheat your oven to 350°F. Grease and line two 8-inch cake pans. Get serious.
Mix the flour, sugar, cocoa powder, baking powder, baking soda, and salt in a bowl.
In a separate bowl, beat butter and eggs until fluffy and suspiciously perfect.
Add coffee, milk, vanilla, and sour cream. Mix until it feels like velvet.
Gradually fold in the dry ingredients. It’ll feel like you’re walking on clouds—except you’re baking.
Divide batter evenly between pans. Bake for 30–35 minutes, or until a toothpick emerges victorious.
Let the cakes cool in the pans for 10 minutes, then transfer to a cooling rack.
For the frosting, beat mascarpone, butter, powdered sugar, vanilla, and heavy cream until smooth.
Stack the cake layers, generously applying frosting between them.
Cover the top and sides with frosting, smoothing it with an offset spatula like a pro.
Chill for 30 minutes, slice, and prepare to blow people’s minds.