Chop 20 Oreos and set aside.
Beat 3 egg whites until they look like this. Set aside.
White cake mix, 1/4 cup flour, 1/4 cup sugar, 1/2 cup melted unsalted butter, and 1 teaspoon vanilla
Mix on low for 3 minutes.
Scrape the sides of the bowl, turn the mixer on low and add 1/4 cup sour cream and 1 cup milk. Mix about 2 minutes scraping the sides as needed. It may be a little lumpy, but it's ok as long as it looks like this.
Gently fold in your egg whites leaving them not completely mixed in. Gently fold in your cookie pieces just until mixed. If you stir too much the cupcakes won't rise properly and the cookie dust could turn the batter grey.
Bake at 325 for about 20 minutes (give or take). You'll know when they're ready because they'll look like this.
Makes a little more that 2 dozen cupcakes.