In a 10- to 12-inch frying pan over high heat, boil 2 cups ruby red grapefruit juice until reduced to 1/3 cup, about 10 minutes. Turn heat to low and whisk in 3/4 cup (3/8 lb.) butter or margarine, in chunks. Serve at once; sauce separates as it stands.
Nutritional analysis per tablespoon.
Servings Makes about 1 cup
* Percent Daily Values are based on a 2,000 calorie diet. Your daily value may be higher or lower depending on your calorie needs.