Why does a recipe need so much baking powder?

It's not necessarily true that a recipe needs "so much" baking powder. The amount of baking powder used in a recipe depends on several factors:

* Type of baked good: Cakes, muffins, and quick breads require more baking powder than cookies or biscuits because they need to rise higher.

* Ingredients: Some ingredients, like buttermilk or brown sugar, can affect the amount of baking powder needed.

* Desired texture: The amount of baking powder can influence the final texture of the baked good. More baking powder will create a lighter, airier texture, while less will result in a denser, heavier texture.

* Baking powder strength: Baking powder comes in different strengths, with "double-acting" being the most common. The instructions on the packaging will specify the correct amount to use.

The primary function of baking powder is to create air bubbles in the batter, which expand during baking, causing the baked good to rise.

Here's why a recipe might use a relatively large amount of baking powder:

* To compensate for a lack of other leavening agents: Some recipes, like quick breads, don't use yeast, so baking powder is the primary leavening agent.

* To create a light, airy texture: Some recipes, like cakes, require a lot of air to create their signature texture.

* To ensure the batter rises properly: If the recipe calls for a lot of dense ingredients, more baking powder may be needed to create enough lift.

It's important to follow the recipe instructions carefully when it comes to baking powder. Using too much baking powder can lead to a bitter taste, a crumbly texture, or even a collapsed baked good.

If you're unsure about the amount of baking powder to use, it's best to consult a trusted recipe or a baking resource.