• Preheat the oven to 350°F.

Prep the Cake Pan

• Butter and flour the sides and bottom a springform pan. Line the bottom with a 9-inch round piece of parchment paper.

Peach Cake Batter

• Whisk together the sugar and cinnamon in a small bowl for the cinnamon sugar topping and set it aside.
• In a medium-sized bowl whisk together the flour, baking powder, baking soda, and kosher salt. Whisk for 30 seconds to ensure the ingredients are well combined and that the baking powder and baking soda are well distributed throughout the flour.
• Crack the eggs into a small bowl. Cut the peaches into 1/2-inch wide wedges and then cut the larger pieces in half.
• Place the unsalted butter, sugar, cinnamon, nutmeg, and vanilla extract in the bowl of a stand mixer. Start the mixer on low and mix for about 20 seconds, then increase the speed to medium and beat until the mixture is creamy and slightly lighter in color, about 2 minutes and 30 seconds. Scrape down the bottom and sides of the bowl and the paddle attachment.
• Add the eggs one at a time, beating after each addition until the egg is fully incorporated into the creamed butter and sugar.
• Add 1/2 of the flour mixture and mix on low until the flour is incoporated. There may be some flour on the sides of the bowl, which is okay. Add all of the sour cream and mix on medium until the sour cream is in incorporated. Add the remaining flour mixture and mix on low until incorporated. Scrape the sides and bottom of the bowl.
• Scrape the sides and bottom of the mixing bowl once more to ensure the batter is well mixed. For stand mixers ingredients often settle on the bottom and don't get completely mixed in with the other ingredients which is why it's important to scrape the bottom of the bowl and mix in any unmixed ingredients by hand.
• Pour half the batter into the prepared springform pan and smooth it into an even layer. Spread half of the peaches across the batter. Sprinkle half of the cinnamon-sugar mixture over the peaches and cake batter. Add the remaining batter and spread it across the top as evenly as possible. Arrange the remaining peaches across the top. Sprinkle the remaining cinnamon-sugar mixture over the peaches and exposed cake batter.
• Bake the cake for 55-60 minutes. The cake is done when the top is a golden brown, center no longer jiggles when you touch the top with your finger, and cake tester inserted near the center comes out clean with no more than a few crumbs clinging to it. If there is any wet batter on the cake tester, the cake is not done. The internal temperature at the center of the cake should be 200-205° F. Use an instant-read thermometer to perform a temperature check.
• Remove the cake from the oven and set the pan on a wire rack. Run an offset spatula around the edges of the cake to loosen it from the sides of the springform pan. Let the cake cool in the pan for 15 minutes. Remove the ring of the springform pan. Let the cake cool completely, before slicing and serving.

Storing the Cake

• Because of the fresh peaches on top, the cake can be stored at room temperature in an airtight container for 1 day. To store it in the refrigerator, cover it with plastic wrap and store in the refrigerator for up to 5 days.