I still have to try the egg whites but agree that just the soda and cake mix makes the cake come out "crumby" If you don't want to use the egg whites try jello. My wife makes this all the time. She adds either a pack of suger free flavored or knox plain jello. You mix the jello with 1 cup of hot water and then mix it in with the soda and cake mix. It comes out very moist. You might want to decrease the water to 3/4 or half but for us the 1 cup works great.