Cinnamon Roll Layer Cake

INGREDIENTS

3/4 cup

unsalted butter (room temperature)

1 1/2 cups

sugar

3/4 cup

sour cream (room temperature)

2 tsp

vanilla extract

large egg whites (room temperature, divided)

2 1/2 cups

all-purpose flour

4 tsp

baking powder

1 tsp

cinnamon

1/2 tsp

salt

3/4 cup

milk (room temperature)

1/4 cup

water (room temperature)

1 1/2 cups

salted butter (room temperature)

1 1/2 cups

vegetable shortening

12 cups

powdered sugar

1 tsp

vanilla extract

1 tsp

cinnamon

1/4 cup

water or milk (room temperature)

5 tbsp

powdered sugar

2 tbsp

light brown sugar (loosely packed)

1 tbsp

ground cinnamon

2 tbsp

water