1 bag of frozen blackberries (Frozen raspberries can be used, too.)
1 1/4 cups sugar
2 cups plain, non-fat yogurt
1/2 cup milk

Place blackberries and sugar in a sauce pan and cook on medium heat until the juice is extracted from the berries, about 10 to 15 minutes. Remove from heat and let cool a few minutes, then push the berries through a sieve or strainer to extract the juice. Discard the seeds and pulp.

Mix the blackberry juice, non-fat yogurt and milk in a glass bowl. Stir or whisk the mixture to thoroughly incorporate the yogurt into the blackberry juice. Taste and add more sugar if needed. Place in refrigerator to chill.

To make the frozen yogurt, place mixture in the frozen tub of an ice cream maker and process about 20 minutes or according to manufacturer's instructions.

For a totally low-fat dessert, serve with Angel Food Cake slices