Who is Amelia Simmons from On Food and Cooking and what is their importance?

Amelia Simmons was the first to discuss the use of pearlash or potash in leavening bread in literature. She wrote a cookbook in 1796, in which, four of the recipes called for the use of the material, made by soaking the ash produced when plant materials are burned, draining off the liquid and drying it to concentrate the remaining substances. This blend of alkaline potassium carbonate was the precursor to baking soda and baking powder, commonly used today in leavening bread.