1/2 c. unsalted butter, softened, plus 1 tbsp.
1/2 c. granulated sugar
1/2 c. packed brown sugar, plus 1/4 c.
1 tbsp. of orange zest
1/2 tsp. vanilla extract
2 large eggs
1 1/2 c. all-purpose flour
1/2 c. yellow cornmeal
2 tsp. baking powder
1/2 tsp. baking soda
1/2 tsp. fine sea salt
2/3 c. full fat buttermilk
2 ripe peaches, cut into wedges
1/2 tsp. apple cider vinegar
Preheat oven to 350 degrees. Using a stand mixer with a whisk attachment, beat the butter, granulated sugar, brown sugar, orange zest, and vanilla on medium-high speed until light and fluffy. Add the eggs, one at a time, beating well after each addition.
Whisk together flour, cornmeal, baking powder, baking soda, and salt. Slowly add the dry ingredients to the wet ingredients. Alternate between the buttermilk and the dry ingredients, beginning and ending with the flour mixture. Beat on low speed just until the mixture is evenly combined. Pour the batter into a greased, 8-inch, nonstick spring-form pan. Bake for 45 to 50 minutes and test with a toothpick–if it comes out clean, the cake is done. Transfer to a wire rack to cool for 10 minutes.
Meanwhile, heat remaining tablespoon of butter in a large skillet over medium heat. Add the peaches and brown sugar, confit (simmer with the sugar) for 5 minutes, or until the peaches start to soften and a syrupy sauce forms. Remove from heat and stir in the apple cider vinegar. Serve with the cake while still warm.