Blueberry Nectarine Upside-Down Cake

Topping: Combine the butter, brown sugar, and cinnamon in a small saucepan over medium heat. Continually stir until the butter is melted and the mixture just starts to boil. Pour the topping into the prepared pan and spread evenly across the bottom.

Wash the nectarines and cut them into ½” slices. Fan the slices out in a single layer over the topping mixture, overlapping each slice. Add the blueberries to the pan in an even layer, covering any space that the nectarines

Vanilla Cake: In the bowl of a stand mixer fitted with a paddle attachment, cream the butter and the sugar until fluffy and light in color, about 3 minutes. Slowly add the eggs and vanilla, combining well after each addition. Scrape the bowl well with a rubber spatula then mix on high for about 1 minute until the mixture is smooth and light in color.

Sift together the flour, baking powder, baking soda, and salt. Add half of the flour mixture and the sour cream to the bowl. Start the mixer on low speed and slowly stream in about half the milk. Mix just until combined then scrape the bowl. Add the remaining flour and slowly stream in the remaining milk with the mixer on low, just until combined. Scrape the bowl again and give the mixture a few final folds with a spatula to ensure everything is incorporated.

Cinnamon Sugar Layer: Combine the sugar and cinnamon in a bowl. Sprinkle the cinnamon sugar mixture over the cake batter in an even layer.

Place the cake pan on a baking sheet, just in case any of the fruit juices seep out while baking. Bake for 48-52 minutes, or until the center of the cake springs back to the touch (or a toothpick comes out mostly clean).

Allow the cake to cool for 10 minutes in the pan. Run a spatula around the edge of the pan to loosen the cake. Invert the cake onto a plate or serving platter by placing the dish on top of the cake pan then carefully but quickly flipping the pan upside down. Lift off and remove the pan. Serve warm or cool to room temperature and enjoy!