Combine peaches and 1/2 cup sugar in a small mixing bowl; stir well, and set aside.
Scald milk and half-and-half in a 3-quart saucepan. Combine eggs, 2 cups sugar, cornstarch, and salt. Stir 1/2 cup hot milk mixture into egg mixture; add to remaining hot milk mixture, stirring constantly with a metal spoon. Cook over medium heat, stirring constantly, 15 minutes or until mixture coats the spoon. Remove mixture from heat, and cool.
Stir in reserved peaches and vanilla; chill 2 hours or overnight. Pour mixture into freezer can of a 1 -gallon hand-turned or electric freezer. Freeze according to manufacturer's instructions. Let ripen 1 1/2 to 2 hours before serving. Spoon into individual bowls, and serve immediately.