1Heat oven to 350°F (325°F for dark or nonstick pan).
2Make and bake cake as directed on box for 13x9-inch pan. Cool completely in pan, about 1 hour.
3Pierce cooled cake all over with fork. In small bowl, stir gelatin and boiling water until smooth; stir in cold water. Pour over cake. Run knife around sides of pan to loosen cake. Refrigerate 2 hours. Frost with whipped topping; garnish with raspberries. Store covered in refrigerator.