Every once in while we run out of "Baking powder".  What would be a good recipe for a substitute that you have used that works well? 
On the off-chance that you have no baking powder, but you do have baking soda and cream of tartar, you can make your own baking powder:   1 teaspoon baking soda 2 teaspoons cream of tartar 1 teaspoon corn starch (optional)   Mix it all together and use it immediately.  Reference: http://frugalliving.about.com/od/condimentsandspices/r/Baking_Powder.htm 