Preheat oven to 350 degrees F. Lightly grease 13 x 9 inch baking pan. Set aside.
2. In large bowl, combine dry cake mix along with water, oil, and egg whites as called for on cake mix box.
3. Blend with electric mixer on medium speed for 2 minutes. Pour batter into prepared pan.
4. Bake at 350 degrees for 26 to 28 minutes or until cake is light golden brown and toothpick inserted into center of cake comes out mostly clean.
5. Remove pan to wire rack to cool.
6. Using two small saucepans, place one cup of water into each saucepan and bring to a boil. Add packet of strawberry gelatin to one saucepan and berry blue gelatin to other saucepan. Stir for 2 minutes.
7. Poke holes into cake using end of wooden spoon or a straw.
8. Use long-handled teaspoon to pour strawberry gelatin into alternating rows followed by berry blue gelatin in remaining rows.
9. Cover and refrigerate for at least 3 - 4 hours to chill.
In large bowl, add in heavy whipping cream, powdered sugar, and vanilla extract.
2. Blend with an electric mixer on high speed for 3 - 5 minutes. Liquid will form into soft peaks and then stiff peaks. Blend until texture has stiffened to whip cream consistency.
3. Use spatula to spread whipped cream topping evenly on top of cake.
4. Keep dessert refrigerated.