Updated January 2012.
If baking powder were an opera, the libretto might read:
Act I: Poor little BP lives a quiet life on a cool, dark shelf. Enter The Baker, who introduces BP to Wet. Bubbles appear.
Act II: The Baker, sensing something dramatic might be happening, then introduces BP and Wet to Heat, and kaboom! Bubbles appear again. The Baker encourages BP, Wet and Heat to travel together to Cookie Land, and they have adventures along the way.
Act III: Out of the oven the Baker pulls beautiful cookies, all puffed up and proud, thanks to BP's double-bubble action.
And they all live happily ever after.
Actually, except for The Baker, they all get eaten in the end...which, of course, is a happy ending for us!
I'm no scientist, which is perhaps why I'm not a good baker, and I'm always a bit confused about the baking powder/baking soda thing. Baking powder is a chemical -- more precisely, a mix of chemicals, usually cream of tartar and either sodium aluminum sulfate or anhydrous monocalcium phosphate -- that produces a controlled reaction when combined with liquids and heat. Nearly all baking powder sold today is double acting, which means that it contains two acids that react at two different times; the quick-acting acid dissolves first, when mixed with liquid, and the slower-acting acid reacts when activated by heat. These reactions release carbon dioxide gas, which causes the batter that's carrying the baking powder to rise.
Rumford (which used to be made right here in Rhode Island) is the best-known aluminum-free brand of baking powder; check your market for others. There are also sodium-free baking powders; if you use them, be sure to double the amount called for in your recipe, as these products are less powderful.
As a rule, baking powder will last 4-6 months if stored in a cool, dry place. To test the viability of your baking powder, drop a generous pinch in some hot water. If it fizzes, it's still good; if it sinks in a blob to the bottom of the bowl, throw it away.
My friend Laura goes to yard sales every Saturday morning, and she brings home the most wonderful old cookbooks. Often they're filled with recipes cut out of magazines, or scribbled on bits of paper and used as bookmarks. This is one of those recipes, source unknown, circa 1979, stuffed into a copy of Woman's Home Companion Cook Book, published by PF Collier & Son in 1942. Here's the recipe, word for word, with all of its charming original punctuation. [Update: see the comments below. Thank you, readers! The recipe is from Peg Bracken's I Hate to Cook Book.]
Makes 2 dozen or more.
3 cups oatmeal
1-1/2 cups flour
1-1/2 cups brown sugar
1-1/2 cups butter
1-1/2 teaspoons baking powder
Dump all ingredients into a large bowl. Mash! Knead! Pound! The longer and harder you mix, the better the cookies will taste!
Roll dough into small balls. Place on cookie sheet and bake at 350 degrees for 10 to 12 minutes.
Other recipes that use these pantry ingredients:
Oatmeal coconut chocolate chip cookies, from Pinch My Salt
Oatmeal cranberry white chocolate chunk cookies, from Cooking on the Side
Chocolate chip cookie bars, from Two Peas & Their Pod
Oatmeal raisin cookies, from Simply Recipes
Whole wheat oatmeal chocolate chip cookies, from 101 Cookbooks
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