Crumble the sponge fingers a little bit and put them into four ovenproof dishes. Drizzle with raspberry brandy. Spread the berries on top. Separate the egg. Mix egg yolk, lemon peel and juice, mascarpone, sugar and vanilla sugar.
Beat the egg white until stiff and fold in. Pour cream over the berries and bake under the hot grill of the oven. Dust with icing sugar and decorate with mint.