Preheat your oven to 350°F (177°C) and prepare a muffin pan by spraying each cup with non-stick cooking spray.

Cut 1 tablespoon of cold unsalted butter into 12 pieces; place one piece in each muffin cup. Sprinkle ½ teaspoon of brown sugar over each piece.

Thinly slice your fresh peaches and arrange the slices decoratively over the sugar and butter.

In a small bowl, whisk together 1½ cups of all-purpose flour, 1 teaspoon of baking powder, ½ teaspoon of baking soda, and ¼ teaspoon of salt.

Beat ⅓ cup of room temperature unsalted butter with ⅔ cup of granulated sugar until fluffy. Add in 1 large egg and 1 teaspoon of vanilla extract, beating until well combined.

Gradually add half of the flour mixture to the butter mixture, then add ½ cup of buttermilk. Mix until smooth. Add the remaining flour and stir until just combined.

Gently fold in the cubed peaches into the batter.

Using a scoop, fill each muffin cup with batter until nearly full.

Bake for 25-30 minutes until a toothpick inserted comes out clean. Allow to cool in the pan for 5 minutes.

Flip the muffin pan onto a wire rack to release the cakes and let cool before serving.