Preheat oven to 350F / 180C. Spray 13x9 pan with cooking spray. Mix cake mix, water, oil, and egg whites on low speed for 30 seconds in a large bowl. Then mix on medium speed for 2 minutes, making sure to scrape down the sides of the bowl. Pour cake mixture into the prepared pan.
Bake for 28-32 minutes. Test the doneness of the cake by inserting a toothpick into the center of the cake. If it comes out clean, it’s finished baking. Remove from oven and cool on a rack for 20 minutes.
Boil water and add the gelatin packet to a bowl. Pour in the boiling water and stir until gelatin is dissolved.
Use a wooden spoon handle to poke holes in the cake about one inch apart, going halfway down into the cake. Carefully pour the gelatin over the whole cake evenly. Cool for at least 1 hour (and 3-4 hours if you have time) in the refrigerator.
Once the cake is cool, use a spatula to spread on the frosting, then add red decorating gel. Use a knife to cut the cake into 4x3 rows. Garnish with strawberries, serve, and enjoy!
Notes
If you don’t have a wooden spoon for poking the cake, you can use a metal fork or a drinking straw.
If you don’t have a ton of time to wait for the gelatin to set and “cool”, try placing the cake in the freezer for about a half-hour and check on it.
If you’re going to use a homemade cake recipe, it will add to your prep time.
Clean your knife after each cut when cutting the cake. The frosting makes the knife very messy and cutting becomes extremely hard.
Keeping your cake in the refrigerator when not being served is helpful so that your icing doesn’t become too soft.
If you find your gelatin isn’t going in the holes well, use a funnel.