Sift flour into a bowl. Gradually add combined egg and 1 cup So Good Now Low Fat, mixing until smooth.
Heat margarine in a frypan. Pour off excess. Add 2 tablespoons batter, rotating pan quickly to coat bottom thinly and evenly. Brown on both sides. Repeat until all batter mixture is used.
Combine custard powder and sugar in a saucepan or bowl. Gradually add lemon juice and add 1 1/2 cups So Good Now, stirring until smooth.
Stir over medium heat until mixture boils and thickens (or microwave on HIGH [100%] for 5 minutes, stirring occasionally.