Preparation - In a large boiler, mix milk, egg yolks and sugar together. Bring to a boil, stirring constantly. Lower heat and cook for about one minute, then add cracker crumbs and coconut (if desired). Remove from heat and stir in vanilla. Pour into a buttered casserole dish. Set aside. Beat egg whites until stiff; fold in 3 T. sugar. Gently spread meringue over top of the pudding mixture. Bake at 350º for 10 to 12 minutes or until the meringue is very lightly browned.