Whip cream, sour cream and icing sugar with the whisk of the hand mixer until creamy. Stir in lemon curd. Pour the sour cream into glasses and chill.
Meanwhile break the spaghettini into 6 pieces of equal size. Put 3 spaghettini each as "whiskers" into the marshmallows. Fasten the "bunny noses" to the glasses with white sugar writing. Decorate the cream with sugar pearls. Stick two sponge cakes into the cream as "bunny ears".