I wanted to try a new recipe for buttercream and decided to try Easy, Never Fail Buttercream by shelleytc10. The recipe calls for Meringue powder. I went to 3 different grocery stores with no luck in finding any. I did find a product called Just Whites. It is 100% dried egg whites. Can I use the Just Whites instead? Anyone know what effect the substitution will have on the recipe? Thanks!