Apple Rosemary Upside Down Cake

Ingredients

For the Cake:

• 2 cups all-purpose flour
• 1 ¾ teaspoon baking powder
• ½ teaspoon fine-grain sea salt
• 4 ounces (1 stick) unsalted butter, room temperature
• ½ cup white granulated sugar
• 2 large eggs
• 1 teaspoon pure vanilla extract
• ¾ cups whole milk

For the Apple Topping:

• 6 tablespoons unsalted butter
• ¾ cup brown sugar
• 1 rosemary sprig, leaves detached
• 1 large honey crisp apple, cored and thinly sliced (equaled to about 1 cup of sliced apples)
• Pinch of flaked sea salt, plus more topping

Instructions

1. 1
   Preheat the oven to 350 degrees F.
2. 2
   In a medium bowl, mix together the flour, baking powder and salt. Next, in a medium bowl, cream together the butter and sugar until light and fluffy, about 2 minutes. Add the eggs and vanilla; and then mix until the mixture is smooth.
3. 3
   To the butter and sugar mixture, mix in half of the flour mixture and the milk. Then, mix in the remaining flour mixture, being sure not to over mix.
4. 4
   In a 12-inch cast iron skillet (*see note below about alternative vessels), melt the butter over medium heat. Mix in the brown sugar, rosemary and salt and stir until the sugar begins to bubble, about 1 minute. Turn off the heat and let stand for a few minutes to cool slightly. Next, arrange the apple slices to your liking. Feel free to layer them a bit, as they’ll shrink during baking.
5. 5
   Pour the batter over the apples, and gently spread the batter so it’s nice and even. Transfer the cast iron skillet to the oven and bake for 35-45 minutes or until a skewer comes out clean.
6. 6
   Remove the cake from the oven and allow to cool for 5-10 minutes. To invert the cake, place a (large enough) plate on top of the cast iron skillet and turn both of them over; lift up the cast iron skillet and voila! Your cake!
7. 7
   Serve this cake slightly warm with a dollop of whipped cream (if desired).