Add cake mix to a large mixing bowl and then using a hand or stand mixer, add oil, egg whites, and soda. Mix on medium until well incorporated, and then mix in *1/2-3/4 of the Jello.
Add batter into the muffin tin until each is about 2/3 full. Bake for 18-20 minutes, or until a toothpick comes out clean. Allow to cool completely on a wire rack before frosting.
Slowly mix in the powdered sugar, 1 cup at a time, while adding a bit of the liquid mixture in between each cup. Continue to mix for 1-2 minutes or until creamy and forms stiff peaks.