Peanut Butter Chocolate Ripple Ice Cream

from Epicurious
yield: Makes about 1 quart

Ingredients
1 2/3 cups whole milk
1 cup creamy peanut butter
1/2 cup plus 3 tablespoons sugar
2 teaspoons vanilla
3 tablespoons water
1 1/2 ounces fine-quality bittersweet chocolate (not unsweetened), chopped

Preparation
In a saucepan simmer milk, peanut butter, and 1/2 cup sugar over moderate heat, stirring, until smooth, about 1 minute.
Stir in vanilla and cool mixture to room temperature.
Freeze mixture in an ice-cream maker according to manufacturer's instructions.
While ice cream is freezing, in a small saucepan simmer water and remaining 3 tablespoons sugar, stirring, until sugar dissolves.
Add chocolate, stirring until smooth, and cool sauce to room temperature.
Spread one fourth ice cream in a 2-quart container and top with one third sauce. Layer remaining ice cream and sauce in same manner and with a spatula swirl sauce and ice cream together.
Freeze ice cream, covered with plastic wrap, until hard.