Many recipes call for baking powder, but who bakes enough to use a whole can before it expires? In fact, I learned the hard way about best-use-by-dates when we tried baking a cake with an old can ...

It depends on storage conditions. Baking soda can last quite a long time if stored sealed in a cool, dry space. Baking powder, however, is problematic. It can last 3 months, or it can last a year.

Combine the sour cream, dry mustard, pepper, salt, garlic powder, and Worcestershire sauce, and blend at low speed for 2 minutes with an electric mixer. Add mayonnaise and continue to blend ...