and 1/2 tsp. of baking powder

Baking powder is a leavening agent composed primarily of sodium bicarbonate (baking soda), one or more acid salts (commonly cream of tartar, monocalcium phosphate, or sodium aluminum sulfate), and a moisture absorber such as cornstarch or potato starch. The acid and base components remain inert when dry but react when moistened and heated, producing carbon dioxide gas that causes baked goods to rise. Most commercial baking powders are "double-acting," meaning they release gas in two stages: once when wet and again when exposed to heat during baking.\n\nBaking powder was developed in the mid-19th century as a more reliable and convenient alternative to yeast or pearlash. Its invention revolutionized home baking by making leavening more predictable and accessible. The ratio and type of acid salt can vary by manufacturer, affecting bake time and final texture.

Baking powder is essential in quick breads, cakes, cookies, biscuits, pancakes, muffins, and scones, where rapid, consistent rise is required without the long fermentation time of yeast. It is typically mixed into dry ingredients before wet ingredients are added, ensuring even distribution and activation only upon hydration. The amount used depends on the recipe's acid content—recipes with acidic ingredients like buttermilk or lemon juice may use less baking powder, while neutral recipes rely on double-acting powder. Baking powder is fundamental to American and European baked goods and is increasingly used in Asian and other global baking traditions.