There are a few ways you can make boxed caked mixes better (when not making cookies out of them). u003cbr/u003e1. Simply replace water with milk for more flavor and moisture. u003cbr/u003e2. If you're making red velvet cake mix you can use buttermilk.u003cbr/u003e3. Replace the oil with melted butter for more flavor and homemade texture.u003cbr/u003eAlways replace these substitutes for the same quantity the packaging calls for.