Recipe(tried): Curtis Aikens Pineapple Upside-Down Cake

I've made this a few times; more work than a regular recipe for this type of cake; but well worth the effort; it is really rich in flavors.

PINEAPPLE UPSIDE-DOWN CAKE (CURTIS AIKENS)

1/2 cup butter
1/2 cup brown sugar
1 large pineapple, cored, sliced into 1/3-inch rings, about 10 rings (I used the pre-cored/sliced from supermarket; and reserve any of the juices in the plastic bag the pineapple comes in.)
1/4 cup dark rum
1/2 cup heavy (whipping) cream

FOR THE CAKE:
2 cups flour
3/4 teaspoon baking powder
1/2 teaspoon baking soda
3/4 teaspoon salt
3/4 cup unsalted butter, softened
1 1/3 cups sugar
3 eggs, separated
1 1/2 teaspoons Tahitian vanilla extract (I used regular vanilla)
1/4 cup fresh pineapple juice
1/2 cup buttermilk

Combine 1/2 cup butter and brown sugar in a 12-inch cast iron skillet and heat until bubbly. Add pineapple and caramelize to a deep golden brown, turning once. Remove from skillet and set aside.

For the sauce, pour rum and cream into a skillet and cook over low heat 5 minutes, until thickened, stirring constantly with a whisk. Remove from heat and set aside to cool.

Butter a 10-inch round cake pan and line with parchment paper. Arrange pineapple rings, to cover bottom of pan. Pour cooled sauce over pineapple and set pan aside.

In a large bowl, cream softened butter and sugar, until light and fluffy. Add egg yolks, one at a time, beating after each addition. Add vanilla; set aside.

Combine pineapple juice and buttermilk.

Alternately add sifted dry ingredients and juice/buttermilk mixture to creamed mixture (begin and end with dry ingredients.) Set aside.

Whip egg whites to soft peaks and fold into batter. Spoon over the pineapple in the cake pan.

Bake at 350 degrees F about 1 hour, or until a tester comes out clean. Invert onto a serving platter.