1. Bring fresh mint leaves and 1 qt. water to a boil in a medium saucepan over medium-high heat. Boil 7 to 8 minutes or until leaves darken; stir in 3/4 cup sugar. Cook, stirring constantly, 2 minutes or until sugar dissolves; remove from heat. Stir in 3/4 cup lemonade concentrate, and let mixture stand 30 minutes.
2. Pour lemonade mixture through a wire-mesh strainer into a large zip-top plastic freezer bag; discard mint leaves. Seal and freeze 8 hours or until mixture is firm. Remove lemonade mixture from freezer; let stand 30 minutes or until slushy, turning bag occasionally. Serve with fresh raspberries, if desired.
*Limeade concentrate may be substituted for lemonade concentrate.
Lemon-Basil Ice: Substitute 2 cups firmly packed fresh basil leaves for fresh mint leaves, and proceed with recipe as directed.