Caramel Apple Upside Down Cake

Preheat the oven to 350 degrees. Combine the butter and brown sugar together in a small saucepan over medium heat. Whisk occasionally until the butter has melted. Cook, whisking constantly, for 1 minute as the mixture thickens. Remove from heat and whisk in the cinnamon and vanilla. Pour into an ungreased 9x2-inch round cake pan or pie dish. Arrange the apple slices neatly on top, overlapping where necessary. Place the pan in the refrigerator for a few minutes as you make the cake batter.

Make the cake batter. Whisk the flour, baking powder, cinnamon, nutmeg, and salt together. Set aside.

Using a handheld or stand mixer fitter with a paddle or whisk attachment, beat the butter on high until it is smooth and creamy, about 1 minute. Add both sugars and beat on high until creamed together, about 1 minute. Scrape down the sides and up the bottom of the bowl with a rubber spatula as needed. On high speed, beat in the eggs and vanilla until combined. Scrape the sides and bottom of the bowl again. Pour the dry ingredients into the wet. Turn the mixer on low speed and, as it runs, slowly pour in the milk. Beat on low just until all the ingredients are combined. Do not over-mix.

Remove the pan from the refrigerator. Pour and spread the cake batter evenly over the topping. Bake for 40 to 45 minutes, tenting foil on top of the cake halfway through the baking time to prevent the top from over-browning before the center has a chance to fully cook. The cake is done when a toothpick inserted into the center of the cake comes out mostly clean. 

Let the cake cool for 15 minutes in the pan. Invert the slightly cooled cake onto a cake plate. Some of the juices from the topping will seep over the sides, and that’s okay. Cool the cake completely before slicing.