Grease an 8 inch (20cm) raised-based flan tin. Sprinkle over 2 tsp sugar and tilt to coat evenly. Add 1 level tsp flour and coat similarly, knocking out any excess
Beat the egg yolks and gradually add 1/2 cup sugar, and beat to a froth. Mix the hot milk with the remaining sugar, lemon juice, lemon peel, and butter