My favorite lemon curd, from Allrecipes.com

3 eggs 1 cup sugar 1/2 cup fresh lemon juice 1/4 cup butter or margarine, melted 1 tablespoon grated lemon zest Directions In the top of a double boiler, beat eggs and sugar. Stir in lemon juice, butter and lemon zest. Cook over simmering water for 15 minutes or until thickened. My note:  Remove from heat immediately and continue stirring so not to curdle your curd.