Preheat your oven to 180 degrees
Beat the egg yolk till it becomes creamy in texture and lemon in colour.
Then gradually add the sugar.
Beat the egg whites till still stiff and fold it into the above mixture with a wooden spoon.Fold in the flour as well.Dont overdo it.
Pour it into a lined baking tin or baking dish and bake for 20 minutes.
Decorate as desired.