NuWave Oven Pro Sprucing up a conventional boxed cake mix! 1. Follow the directions listed on the box. 2. Add one or two additional eggs. 3. Instead of oil, use melted butter and double the amount. 4. Use milk instead of water. 5. Mix well and bake on the 2-inch rack on Power Level 8 for 50 minutes, using the Extender Ring. 6. Add chocolate frosting (optional).