Melt the butter in a microwave-safe container. Beat the egg with a fork until frothy. Mix the sugar and vanilla sugar with the egg. Add the cream cheese and stir until smooth. Mix the baking powder and flour with the mixture and stir in the lemon aroma and butter. Mix the blueberries into the batter.
Put the dough in a greased cup or a microwave-safe container and bake at 600 watts for about 4 minutes.