Low-Fat Lemon Raspberry Cake

INGREDIENTS

• cooking spray
• Cake batter:
• 1 (18.25 ounce) package lemon cake mix
• 1 (3 ounce) package sugar-free lemon pudding mix
• 1 1/4 cups water
• 1/2 cup fat-free sour cream
• 1/2 cup egg whites
• Filling:
• 1 (12 ounce) package frozen raspberries, thawed and drained (reserve drained liquid)
• 1 1/2 teaspoons cornstarch
• Frosting:
• 1 (8 ounce) container fat-free lemon yogurt
• 1 (8 ounce) container reduced-fat frozen whipped topping, thawed