Vanilla Bean and Caramel Cake

This cake is really tempting. I love those flavors and �rustic� looking food.

3 1/2 cups cake flour (such as Swan's down, do not substitute homemade cake flour)
1 Tbsp. plus 1 tsp. baking powder
1/2 tsp. salt
4 large egg whites, at room temperature
2 egg yolks, at room temperature
1 1/2 cups whole milk, room temp
1 cup unsalted butter, softened
1 1/2 cups sugar
1 tsp. vanilla extract (I used Rodelle)
1 vanilla bean, seeds scraped out and pod discarded (I used Rodelle)
Caramel Icing
3 cups (light) brown sugar, firmly packed
1 cup plus 2 TBSP heavy whipping cream
4 TBSP unsalted butter
1 tsp. vanilla extract (I used Rodelle)
1 cup powdered sugar