Preheat your oven to 325 degrees.
In a small bowl, combine ½ tsp cinnamon and the brown sugar together
Generously butter a 9-inch Bundt pan and sprinkle the sugar mixture to evenly coat the inside of the pan. Set aside
In a medium bowl, mix the peaches with 2 tsp cinnamon and ½ tsp nutmeg until coated. Set aside
In a large bowl, whisk together flour, baking powder, salt, and the remaining cinnamon and nutmeg until combined. Set aside
In a medium bowl using a hand mixer with a beat the egg whites until they reach medium peaks (about 3 minutes). Set aside
In a large bowl, cream together the butter and granulated sugar at medium speed until light and fluffy (3-4 minutes)
Add in the egg yolks one at a time, mixing well after each addition
Add in the peach schnapps and vanilla and mix well
Slowly add the flour mixture into the wet ingredients and mix until just combined
Using a spatula, gently fold the egg whites and buttermilk into the batter
Pour half of the batter into the prepared pan and top with sliced peaches
Pour the remaining batter over top of the peaches and use a spatula to smooth them out
Bake in preheated oven for about 90 minutes, or until a toothpick inserted in the center comes out clean
Remove the pan from the oven and allow it to sit for 10-minutes. Once 10-minutes has passed, place your cooling rack over top of the pan and carefully flip onto the rack. Gently lift the pan and allow the cake to cool