How many cups cake flour equal to 3 all-purpose flour?

You can't directly substitute cake flour for all-purpose flour in a 1:1 ratio. Cake flour has a lower protein content, making it lighter and more delicate.

Here's how to convert 3 cups of all-purpose flour to cake flour:

1. Reduce the amount: You'll need less cake flour than all-purpose flour. A good starting point is to use 2 1/4 cups of cake flour for 3 cups of all-purpose flour.

2. Add cornstarch: Cake flour is lower in protein, so to get the same texture, you'll need to add a bit of cornstarch. Add 2 tablespoons of cornstarch to the 2 1/4 cups of cake flour.

Why does this work?

* Lower protein: Cake flour has less protein than all-purpose flour. Protein in flour develops gluten, which gives bread its chewy texture. Cake flour produces a softer, more tender cake.

* Cornstarch: Adding cornstarch helps mimic the low-protein content of cake flour.

Important Note: This is an approximation. It's always a good idea to test a small batch of your recipe to make sure you like the texture before making a full cake.