Cinnamon Swirl Layer Cake

INGREDIENTS

2 1/2 cups

cake flour or bleached all purpose flour

4 tsp

baking powder

1/2 tsp

kosher salt

3/4 cup

unsalted butter, room temperature*

1 1/2 cups

granulated sugar

3/4 cup

sour cream, room temperature

2 tsp

vanilla extract

large eggs, room temperature

large egg whites, room temperature

1 cup

whole milk

1/4 cup

granulated sugar

1 tbsp

ground cinnamon

4 sticks

unsalted butter (use all or half cultured butter for a more flavorful frosting)

1/4 cup

heavy cream

1/4 tsp

kosher or fine sea salt

4 cups

sifted powdered sugar (more or less as needed)

1 tsp

vanilla extract