Baking powder usually comes in aluminum tins with plastic lids. I was ignoring this for a while since I didn’t really know what to do about it, but I’ve come up with a solution. Its really simple and its plastic free. Here’s what you need to make your own baking powder:
- 1 teaspoon baking soda
- 2 teaspoons cream of tartar (My cream of tartar has a plastic lid, but once I use it up I’m going to start buying it in bulk.)
Combine baking soda and baking powder. Use immediately. If you want to store your baking powder, add a teaspoon of cornstarch to the mix.
The Plastic-Free Chef 
This is Genius!
Why do you need to add cornstarch to store it? Is it to prevent caking? I love your recipes. I will try to make some things I thought were not possible in a plastic free life, such as goldfish!