Warm Apple and Sweet Potato Upside-Down Cake with Caramel Sauce

• 5 tablespoons unsalted butter
• 3/4 cup packed dark brown sugar
• 2 large baking apples (such as Granny Smith, Braeburn, or Jonathan), peeled, cored, and each cut into 8 wedges
• 5 tablespoons unsalted butter, at room temperature
• 1/2 cup packed dark brown sugar
• 1/2 cup granulated sugar
• 1 teaspoon vanilla extract
• 1 1/2 cups mashed cooked sweet potatoes (such as garnet yams)
• 2 large eggs
• 1 1/4 cups all-purpose flour
• 1/2 teaspoons baking soda
• 1 teaspoon baking powder
• 1/2 teaspoon kosher salt
• 1 1/2 teaspoons ground cinnamon
• 1 teaspoon ground ginger
• 1/2 teaspoon ground cardamom
• 1/4 teaspoon freshly grated nutmeg
• 3/4 cup buttermilk
• Creme fraiche or warm Cinnamon-Caramel Sauce (page 179), for serving

1. Prepare a medium heat fire (350F) in a wood-fired oven, or in a cooker or grill prepared for cooking with indirect heat.
2. Melt the butter in a 10-inch cast-iron skillet.
3. Stir in the brown sugar.
4. Arrange the apple sections in a circular pattern, rounded side down, on top of the sugar.
5. Use the last section of the apple to fill the center.
6. Bake in the oven or on indirect heat in a covered grill for 15 minutes.
7. At this point, the apples should be half-submerged in the syrup and very soft.
8. While the apples are baking, prepare the batter.
9. Beat the butter and sugars together in a stand mixer until fluffy and smooth.
10. Beat in the vanilla, sweet potatoes, and then the eggs, one at a time, until smooth.
11. Sift the flour, baking soda, baking powder, salt, and spices into a separate bowl.
12. Add this dry mixture to the batter in thirds until it is incorporated.
13. Pour in the buttermilk and beat the batter on medium speed for 1 minute.
14. Pour the batter over the hot apples and their syrup.
15. Bake in the oven or over indirect heat in a cooker or grill for 35 to 40 minutes, or until the cake is golden and springs back when you push on the center.
16. Let the cake cool for 5 to 7 minutes, then unmold it onto a large flat platter or plate with a well.
17. Let stand for 10 to 15 minutes to soak up the syrup.
18. Cut into wedges and serve slightly warm, with a dollop of creme fraiche or a drizzle of warm caramel sauce.

unsalted butter, brown sugar, baking apples, unsalted butter, brown sugar, granulated sugar, vanilla, potatoes, eggs, flour, baking soda, baking powder, kosher salt, ground cinnamon, ground ginger, ground cardamom, freshly grated nutmeg, buttermilk

Taken from www.epicurious.com/recipes/food/views/warm-apple-and-sweet-potato-upside-down-cake-with-caramel-sauce-391849 (may not work)