Baking Powder (Best Option)
3 teaspoons per 1 teaspoon baking sodaBaking powder contains both an acid and a base, enabling it to release carbon dioxide gas when moistened and heated, which helps doughnuts rise properly. It compensates for the lack of baking soda's alkalinity by providing a balanced leavening system.
To use baking powder effectively, increase the quantity to about three times the amount of baking soda called for, as baking powder is less potent. Watch for over-leavening which can cause a crumbly texture.
Compared to baking soda, baking powder produces a slightly different crumb structure and may result in a less pronounced browning effect, but it maintains the light, airy texture essential for doughnuts.