Instructions

1. 1
   Lightly beat egg yolks.
2. 2
   Mix the sugar and flour together, then add the lemon juice and zest, yolks, butter and salt.
3. 3
   Stir in the milk and mix well.
4. 4
   Whip the egg whites until stiff and fold into the first mixture.
5. 5
   Pour batter into custard cups or ramekins.
6. 6
   Set the cups in a pan of hot water and bake at Oven temperatures for about 40 minutes.