Prepare the sauce several days ahead, chill it, and reheat just before serving. You can also use this sauce for fondue.
1 1/2 cups 2% reduced-fat milk
1/4 cup half-and-half
1 tablespoon butter
8 ounces bittersweet chocolate, chopped
2 teaspoons grated orange rind
1 1/2 tablespoons fresh orange juice
1 teaspoon Grand Marnier (orange-flavored liqueur)
12 cups vanilla fat-free frozen yogurt
How to Make It
Heat milk and half-and-half in a heavy saucepan over medium-high heat to 180° or until tiny bubbles form around the edges (do not boil). Remove from heat; add butter and chocolate, stirring until smooth. Stir in rind, juice, and liqueur. Serve sauce with frozen yogurt.