You may have noticed that I always start my cake recipes with: “beat butter until fluffy. Add sugar and beat for a few more minutes, until fluffy. Then add eggs and beat some more.” This is because gluten-free flours aren’t as elastic as gluten flours and are somewhat heavy. You need to give the leaveners something to work with. By beating the sugar and then the eggs for a longer-than-you-might time, you are creating air bubbles in your batter. This is important because yeast and chemical leaveners like baking powder and baking soda do not create new air bubbles. They use the air bubbles that are already present to help the crumb to rise. Lots of air bubbles means a light cake instead of a leaden cake.
I learned this trick from Shirley O. Corriher, from her book Cookwise. She has new book out, Bakewise, which I am dying to get. Both books have won the James Beard Cookbook Award. She is in my pantheon of cooking/baking goddesses. (Seriously, one of these days I need to write a book about the bakers and cooks who have most influenced me. It will be a long love letter).
So, anytime you bake a gluten-free cake or bread, please beat the butter and eggs for a long time. The little extra time you take will pay off in a lighter result.
Of course, you don’t need to do this for cookies, which are by nature flat, unless you want a cake-y cookie.
PS: This also works for baked goods containing gluten.