Make 2 sponge cake layer following my easy and delicious recipe in the following link.
Combine the strawberries, granulated sugar and lemon juice in a saucepan. Cook for 10 minutes, then blend and chill in the fridge.
Mix the mascarpone, heavy cream and powdered sugar with an electric mixer until smooth.
Cut out the bump on the sponge cakes, top the first layer with the mascarpone frosting, fruit slices and strawberry coulis, and close with the second layer.
Add more mascarpone frosting, fruit, and strawberry coulis to the top of the cake to decorate.
Leave the cake to rest in the fridge for an hour before cutting and serving.