Preheat oven to 325°F. Spray the inside of 1-1/2-quart glass casserole with butter-flavored nonstick cooking spray. Sprinkle almonds over bottom of casserole. In medium bowl, with electric mixer, beat egg whites at high speed until soft peaks form. Gradually add 1/4 cup sugar, beating until medium-stiff peaks form; set aside. With same beaters, in large bowl, beat together margarine and remaining 3/4 cup sugar. With same beaters, in small bowl, beat egg yolks well; add to margarine-sugar mixture, beating thoroughly. Add flour, salt and lemon juice; beat well. Stir in milk and lemon peel until blended. Stir in 1/3 of the egg white mixture, then gently fold in remaining egg whites. Pour batter into prepared casserole over almonds. Place casserole in shallow baking pan filled with 1 inch hot water. Bake, uncovered, for 50 to 55 minutes, or until golden brown and top springs back when lightly touched with finger. Carefully remove from water and let set for 20 to 30 minutes. Serve warm or chilled. Garnish each serving with lemon half-cartwheel slices and fresh mint leaves, if desired.