Prepare the Base: In a small bowl, add 3 tablespoons of hot water to 1 teaspoon of instant coffee and stir until dissolved.
Make the Batter: In a large mixing bowl, beat the eggs with the dissolved coffee, sugar, vanilla sugar, and a pinch of salt until creamy (about 10 minutes).
Combine Dry Ingredients: Mix the flour, cocoa powder, and baking powder together in another bowl, and sift into the egg mixture. Gently fold to combine.
Bake the Cake: Grease and flour a 26 cm baking pan. Pour the batter into the pan, smoothing out the top. Bake in a preheated oven at 180 degrees Celsius (top/bottom heat) for approximately 30 minutes. Perform the toothpick test to make sure it’s done.
Prepare the Filling: Soak 8 sheets of gelatine in cold water. In a separate bowl, combine 100 ml hot water with 3 to 4 teaspoons of instant coffee and set aside to cool.
Make the Cream: In a large bowl, mix 2 packets of mascarpone and 120 g of powdered sugar. In another bowl, whip 2 packets of cream with vanilla sugar until stiff. Once the coffee mixture has cooled, add it to the mascarpone mixture and stir gently.
Incorporate Gelatine: Dissolve 2-3 teaspoons of whipped cream with the soaked gelatine and add this mixture back to the mascarpone cream. Carefully fold in the rest of the whipped cream until smooth.
Assemble the Cake: Cut the sponge cake horizontally in half. Spread strawberry jam on the bottom layer, place a baking ring around, and layer some coffee cream on top. Add the second sponge layer and cover it with the remaining cream.
Chill and Serve: Chill the cake in the refrigerator for a few hours before serving, allowing the flavors to meld beautifully!
