This is my personal preference, but I think it works better to bake your own angel food cake. You can buy one of the pre-made ones at the grocery, but they're a lot more dense, so the cream cheese mixture doesn't soak in as much. It's also cheaper to bake your own. It's your call!
I apologize that I don't have process pictures for you on this recipe...I was still having some camera issues. You'll find the recipe below, but it's really very simple. You just tear or cut your angel food cake into good-sized cubes, mix with a delicious cream cheese mixture, then layer with sliced strawberries and blueberries. It's a fabulous and easy dessert. And it's pretty, too!
Mike Slider's Mom (Mrs. Slider...I don't know her first name)
16 oz fat-free cream cheese
1 cup low-fat vanilla yogurt
2 tsp. vanilla
1 cup powdered sugar
8 oz fat-free whipped topping
1 angel food cake, cubed
4 pints fresh strawberries, sliced
1 pint fresh blueberries
4 Tbs. sugar substitute (Splenda)
Combine cream cheese and powdered sugar in a large mixing bowl. Beat on high speed until well-mixed.
Stir in vanilla yogurt and vanilla.
Fold whipped topping into cream cheese mixture. Add cake and stir gently to coat well.
In a bowl, combine the sliced strawberries wtih the sugar substitute. Layer the strawberries, blueberries, and cream cheese mixture in a trifle bowl, beginning and ending with the strawberries.