how to make baking powder without cornstarch
How to make it. 1  If your recipe calls for... 2  1 tsp. of baking powder, add instead 1/2 tsp. cream of tartar and 1/4 tsp. baking soda. 3  1 1/2 tsp. of baking powder, add instead 3/4 tsp. cream of tartar and 3/8 tsp. baking soda (1/4 plus 1/8 tsp.). To make a large batch of baking powder, mix Â¼ cup starch (arrowroot or tapioca) with Â¼ cup of baking soda and Â½ cup of cream of tartar. The starch is very important! Otherwise you get concrete. Keep in a sealed jar or Tupperware. 1 tsp. mix equals 1 tsp. baking powder.