Peach Cobbler Coffee Cake

1. Preheat the oven to 350ºF and prepare a 9-inch spring form pan with non-stick baking spray and parchment paper.
2. Combine the cinnamon sugar ingredients in a small bowl and set aside.
3. In a medium bowl, prepare the brown sugar streusel by combining the flour, brown sugar, cinnamon, and salt together and pouring the melted butter in. Mix together until crumbs form and set aside.
4. In a stand mixer or large mixing bowl with electric beaters, cream the butter and sugars together on high for 2 minutes or until light and fluffy.
5. Add in the sour cream, eggs (if using), and vanilla, and mix until fully combined and smooth. Note that depending on the temperature this mixture might appear to be curdled or have separated. Rest assured, it has not.
6. Add in the flour, cornstarch, baking powder, and salt and begin to mix on low. With the mixer running on low, slowly pour in the milk and mix until just combined. Be careful to not overmix the batter at this point. A few streaks of flour showing are totally okay.
7. Pour approximately half the cake batter into the prepared pan and spread evenly.
8. Top with the cinnamon sugar mixture.
9. Pour the remaining cake batter on top of the cinnamon sugar layer and gently spread evenly.
10. In a circular motion starting on the outer edge, arrange the peach slices on top of the cake batter. See the picture above for reference. 
11. Top with the brown sugar streusel and spread evenly.
12. Bake for 40-50 minutes or until the top and edges are golden brown, have pulled away from the pan, and a toothpick inserted in the center comes out clean. Remove from the oven and allow to fully cool in the pan on a cooling rack.
13. Once fully cooled, remove from the pan and top with a simple glaze and fresh peaches if desired. Enjoy!
14. Store any leftover cake in an airtight container at room temperature for up to 3 days or frozen for up to 6 months.