Any ideas? I hear baking is such a precise science, but I am completely at a loss with American recipes here. ← I don´t think it is as simple as substituting the amount of yeast for the equivalent of baking powder or soda. I'm not a master on yeast matters, but somewhere I read that if you have no baking powder, you can substitute each teaspoon of it with 1/4 teaspoon baking soda + 1/2 teaspoon cream of tartar. Hope it helps!