Thaw berries, if frozen. Do not drain. Place half of the berries in a blender container or food processor bowl. Cover and blend or process until berries are smooth. Press berries through a fine-mesh sieve; discard seeds. Repeat with remaining berries. (You should have about 1-1/4 cups sieved puree.)

In a small saucepan stir together sugar and cornstarch. Add sieved berries. Cook and stir over medium heat until thickened and bubbly. Cook and stir for 2 minutes more. Remove from heat. Transfer to a small bowl. Cover and chill at least 1 hour before serving. Serve over angel food cake, cheesecake, or ice cream. (Cover and chill any leftovers for up to 1 week.) Makes about 1 cup sauce. Nutrition Facts are given for 2 tablespoons of sauce.

Prepare as above, except substitute 3 cups fresh strawberries or one 16-ounce package frozen unsweetened whole strawberries, thawed, for the raspberries and do not sieve; use a medium saucepan and reduce sugar to 1/4 cup. (You should have 1 3/4 to 2 cups puree.) Makes about 2 cups sauce.