01 -
Heat your oven to 350°F (standard). Line a 9x9-inch pan with parchment paper and grease it with butter or oil.
02 -
If you don’t have buttermilk, blend 2 tsp vinegar or lemon juice into 2/3 cup milk, stir it, and set it aside.
03 -
Stir together the sugar, flour, salt, baking powder, and baking soda in a mixing bowl. Sift if needed to keep it lump-free.
04 -
Crack in the egg, add the vegetable oil, and pour in the buttermilk. Whisk gently until it’s just mixed together.
05 -
In another small bowl, blend the cocoa powder, boiling water, and instant coffee. Whisk until you get a glossy mix—it enhances the chocolate’s richness.
06 -
Pour the cocoa mixture into the cake batter and fold it gently with a spatula. Don’t overmix.
07 -
Spread the batter evenly into the prepared pan. Bake on 350°F for 23-25 minutes, until a toothpick slid in the middle comes out slightly crumbly.
08 -
Let the baked cake sit in the pan for 20 minutes to cool down.
09 -
Whisk the cold cream, vanilla, and sugar just until it thickens. Don’t overdo it.
10 -
Little by little, add mascarpone into the cream mixture. Mix on low until smooth but avoid overblending to keep the texture fluffy.
11 -
Once the cake is cool, gently take it out of the pan. Trim off the edges, but try not to waste much. Enjoy the scraps if you’d like!
12 -
Clean out the pan, place two sheets of parchment paper inside with overhanging edges, and gently pop the cake back in with the cut side facing up.
13 -
Lightly brush strong coffee or espresso over the cake using a pastry brush. Go over each section once without drenching it.
14 -
Use an offset spatula to evenly spread the mascarpone mixture over the top of the cake.
15 -
Pop the cake in the fridge for about 6 hours, or ideally let it rest overnight.
16 -
Once fully set, use the parchment paper edges to carefully lift the cake and set it on a serving tray.
17 -
If desired, neaten up the sides by trimming. Then sift a light layer of cocoa powder over the top.
18 -
Cut into pieces, serve, and dig in!