Before it became vogue to use "Baking Powder", for uncountable centuries leavening was done the old fashioned way. For more then 10,000 years, it was done through the use of our busy little sourdough critters. For nearly that long, about 7,000 years, it was done with the precursor to what we now refer to as "baking powder."
The basic recipe for modern baking powder consists of baking soda, cream of tartar and/or aluminum sulfate, and corn or wheat starch--a formula designed to ensure that the chemical reaction that causes leavening happens at the right time. Baking powder is a necessary ingredient in baked goodies of all types, including my orange-cranberry biscotti and cornbread.
If you must use commercial baking powder, use Rumford Baking Powder. It's one of the few "modern" baking powders that does not contain aluminum (linked by some research to Alzheimers).
OTOH; if you're like me, you like making EVERYTHING from scratch with basic, healthy, time-tested materials. Using the simple recipe below, you can replace the chemical laden baking powder in all of your recipes. As a bonus, you'll get something that's better for you to boot.
Dry mix the ingredients in the desired amount. Use 1:1 in place of store-bought. Stored in a cool dry place this "baking powder" will last for years.
When using any baking powder or other dry ingredient in a recipe, be sure to sift it along with the flour and other dry ingredients, in order to distribute it evenly and eliminate any clumps.