Assorted fresh fruit Unfrosted cake or frozen Nonfat yogurt, optional In a small saucepan, combine sugar, cocoa and cornstarch; stir in evaporated milk. Cook over low heat 3 minutes, or until mixture boils, stirring constantly with whisk. Continue cooking 1-2 minutes longer, or until sauce is thickened and smooth, stirring constantly. Remove from heat; stir in vanilla. Serve warm or cold with fresh fruit, cake, or nonfat frozen yogurt. Cover and refrigerate leftover sauce.