Easy Raspberry Trifle
["1 pkg. Betty Crocker 1-step white angel food cake mix", "2 c. boiling water", "1 (8 serving size) pkg. sugar-free raspberry flavored gelatin", "2 (10 oz.) pkg. frozen, sweetened raspberries, thawed", "2 (8 oz.) containers raspberry low-fat yogurt"]
["Bake and cool cake as directed on package for angel food (tube) pan.", "Tear cake into about 3/4-inch pieces."]
["cake mix", "boiling water", "sugar-free raspberry flavored gelatin", "raspberries", "containers"]