2 fresh lemons, sliced
1 egg yolk
2 tbsp. flour
1 c. sugar
1/2 stick butter
1 1/2 c. water

Put slices lemons in saucepan. Add water; boil until lemon skins are done. Strain to remove seeds and peeling. Stir in briskly egg yolk, sugar and butter. Mix flour with water, 2 tablespoons, and stir in to thicken filling. Add more flour if needed. Cook slowly.