Bake in a preheated 350 degree oven

1. Beat the butter and sugar in a large mixing bowl for about 5 minutes, until light and fluffy.

2. Sift together flour, baking powder and salt and set aside.

3.Whisk the egg whites, milk and vanilla extract together until well blended.

4. Add the flour alternately with the egg mixture while beating with an electric mixer. Always start with flour and end with flour. Add 1/3 of the flour to the butter mixture and beat until incorporated, add egg mixture, beat until incorporated. Repeat with flour, then egg mixture and lastly flour. Only beating until just incorporated. Scraping bowl often.

5. Pour batter into prepared 9x13 inch greased baking pan, smoothing batter to edges of pan. Bake 25 to 30 minutes testing with a toothpick for doneness.

6. Cool cake completely. With the handle of a wooden spoon poke holes in the cake.

In medium bowl, stir together filling ingredients (mixture will thicken). Pour over cake; spread evenly over surface, working back and forth to fill holes. (Some filling should remain on top of cake.) Refrigerate 1 hour.

1. Refrigerate a large mixing bowl about 15 minutes to chill.

2. In a small saucepan sprinkle unflavored gelatin over the cold water, let sit for one minute to dissolve. Over low heat, cook the gelatin about 3 minutes until it is completely dissolved, cool to room temperature.

3. Place whipping cream in the large chilled bowl. With the electric mixer on low, pour gelatin into whipped cream in a steady stream and mix until well blended. With the mixer on medium speed continue to beat whipped cream until thickened. With electric mixer on high speed, gradually add powdered sugar and beat until stiff peaks form. Spread whipped cream on top of cake.

If you're making this cake semi homemade use your favorite brand of white boxed cake mix, example... Betty Crockers Super Moist White Cake Mix. Add 1 1/4 cups water, 1 Tablespoon vegetable oil and 4 eggs to the dry cake mix. Beat ingredients about 2 minutes scraping bowl. Pour batter into a greased 13x9 inch baking pan. Bake at 350 degrees about 30 minutes, testing with a toothpick for doneness. Let cake cool completely. Poke holes in the baked cooled cake with the handle of a wooden spoon. Make the homemade key lime filling (recipe above), spread the filling over top the cake, filling the holes, there will be filling that settles on top of the cake. Refrigerate 1 hour. Top with a container of Cool Whip.