Preheat the oven to 180 degrees Celsius and prepare the cake pans with butter and flour to ensure the cake does not stick while baking and comes out easily.
Make the buttermilk: Add the vinegar to the milk and let it sit for 10 minutes.
60 ml full-fat milk, 1 tbsp vinegar
Combine the dry ingredients – flour, white sugar, brown sugar, cocoa powder, baking powder, baking soda, salt, and coffee powder using a hand whisk.
60 grams all-purpose flour, 50 grams white granulated sugar, 50 grams brown sugar, 20 grams cocoa powder, 1/2 tsp baking powder, 1/4 th tsp baking soda, 1/4 th tsp salt, 1/4 th tsp coffee powder
Add the buttermilk, oil, egg, and vanilla essence in the same bowl, and whisk until everything is well combined.
30 ml neutral oil, 1 egg yolk, 1/2 tsp vanilla essence
Gradually pour the boiling water into the batter while whisking and keep mixing until the water is well incorporated.
60 ml boiling water
Pour the batter into the cake pans and bake for 20-30 mins or until a test toothpick comes out clean from the center.
Make the filling: Mix the chocolate paste with the wafer or chopped nuts until combined.
100 grams chocolate paste, 50 grams feuilletine wafers
Make the chocolate ganache: Heat the cream on medium flame until it almost starts boiling. Meanwhile, place the chocolate in a heat-proof bowl. Pour the hot cream on top of the chocolate, let it sit for a minute, then whisk until the chocolate is completely melted and combined.
50 grams milk chocolate chips, 50 ml liquid whipping cream/heavy cream