Grease 6 6oz ramekins, heat oven to 325. Boil water for a water bath.
Mash with the back of a woode spoon: 2/3 c sugar 2 t unsalted butter, softened 1/8 t salt Beat in 3 large egg yolks Add and mix until smooth: 3 T flour (I use 2 rice and 1 tapioca) Gradually beat in 3 t lemon zest and 1/4 c lemon juice (about 1 lemons worth) Stir in 1 c milk Beat in a large bowl until stiff but not dry: 4 large egg whites, room temp Whisk whites into milk mixture, ladle into ramekins, bake in a water bath (hot water halfway up) for 30 to 40 mins until puffed, golden brown, and spring back when pressed. Let stand for 10 mins in water bath. Serve warm, room temp or chilled, in the mold or turned out, as I did here. I've also made these with chocolate instead of lemon. Yum.