Preheat oven to 350°F. Spray three 8 inch cake pans with baking nonstick spray. Line the bottom with 8 inch parchment circles. Spray again.
In a mixing bowl, sift the cake flour. Mix in salt, baking powder, and baking soda. Wash and dry cranberries. Mix cranberries with 1 tablespoon flour. Set aside.
3 ⅓ cup Cake flour, 1 teaspoon Salt, 2 teaspoon Baking powder, ¾ teaspoon Baking soda, 3 cups Wisconsin cranberries, 1 tablespoon Cake flour
Using a mixer, beat butter and sugar on high for 3 minutes. Scrape the bowl. Add in sour cream, vanilla, eggs, and egg white. Beat on high for 2 minutes.
1 ¼ cups Unsalted butter, 1 ¾ cup White granulated sugar, 3 Large eggs, 1 Egg white, 1 tablespoon Pure vanilla extract, ¼ cup Sour cream
Add ⅓rd of the dry ingredients and half of the buttermilk. Mix until it starts to combined. Add another ⅓rd of the dry ingredients and the rest of buttermilk. Finish with the rest of the dry ingredients.
1 cup Buttermilk
Take the bowl off the mixer. Scrape the bowl. Fold in the cranberries into the batter. Separate the batter evenly into the three cake pans.
Bake the cake for 26-30 minutes. Bake until a toothpick inserted comes out clean. Let the cakes sit for 10 minutes before transferring to a cooling rack. Cool cakes completely.