Pineapple Upside Down Cake

This was my Father in Laws favorite cake. He requested it for his birthday every year. He died in February of 1989, but I'm sure if he were here he would LOVE this cake. Today is his birthday, so the kids & I made this cake in memory of him.

ingredients
	11/2 cups all-purpose flour (spooned and leveled) 2 teaspoons baking powder 1/4 teaspoon salt 6 tablespoons unsalted butter, room temperature, plus 3 tablespoons (cut into small pieces) for preparing the top 1 cup sugar, plus 2/3 cup for preparing the top 2 large eggs 1 teaspoon vanilla extract 1/2 cup milk 7 thin rounds cored pineapple

1. Preheat oven to 350°. In a large bowl, combine flour, baking powder, and salt; set aside.
2. With an electric mixer, cream 6 tablespoons butter and 1 cup sugar until light and fluffy. Add eggs and vanilla; beat until combined. Add flour mixture in three additions alternately with the milk in two, beginning and ending with the flour. Mix just until combined.
3. In a 10-inch cast-iron (or ovenproof nonstick) skillet, pour the remaining 2/3 cup sugar into skillet, and place over medium heat.
4. Let sugar begin to liquefy, then stir with a wooden spoon until sugar is fully melted and golden, 2 to 3 minutes. The sugar may smoke, but if it browns too quickly, remove pan from heat briefly before continuing.
5. Remove pan from heat; add 3 tablespoons butter (cut into small pieces), stirring to incorporate. The butter will help cool the caramel and stop it from darkening; it also thins out the caramel to make a syrupy sauce.
6. Begin by placing one pineapple round in the center of the pan. Arrange the remaining rounds in a circle around center slice, overlapping slightly if necessary to fit.
7. Carefully spoon batter over pineapples in skillet. Bake until a toothpick inserted in the center comes out clean, about 45 minutes. Let cake cool in pan 5 minutes. Run a knife around edge of cake, then carefully invert onto a platter. Serve warm or at room temperature.