I currently have no baking powder in the cupboard and I'm just wondering if i can use yeast in a cookie dough recipe instead of baking powder
Your usual cookie recipe can't simply be adapted, but there are plenty of yeast cookie recipes (chocolate chip example). Some of them look rather interesting, but unlike the one I linked have significant rise times.
If you would be baking a cake, I would say there’s a good chance it would work. However the mechanism of action of yeast is not compatible with the usage of baking soda in baking cookies. For the following two reasons:
- Cookie dough doesn’t really have much water content compared to other doughs and batters, and baking soda needs acidity and water to create the leavening effect. As you’re baking the dough, the butter will melt and create the right conditions for the baking soda to work. You’d want the leavening effect to be almost instantenous (or in a really short amount of time) in the oven so that as the CO2 escapes the dough in an instant, it will increase the surface area of the cookie and create the crips/crunch texture you’re accustomed to.
- Baking soda also increases the pH of the dough, which results in prolonging the coagulation of the proteins (especially egg-proteins) and result in a flatter cookie (as you’d like to have). And higher pH also means promoted Maillard reaction, which will result in darker crust cookies.