Preheat the oven to 350°F (177° C). Spray muffin pan with non-stick cooking spray.

Cut 1 tablespoon of butter into 12 equal parts. Place each butter piece in 12 muffin cups.

Sprinkle ½ teaspoon of brown sugar into each muffin cup.

Slice 1-2 peaches into thin slices. Arrange about 3 slices into the bottom of each muffin pan.

Cut the remaining peaches into small cubes. Set aside.

In a small bowl, whisk together flour, baking powder, baking soda and salt.

In a mixing bowl with paddle attachment, beat butter and sugar together until fluffy and creamy, about 2 minutes.

Add egg and vanilla extract and beat for another 2-3 minutes until well combined.

Add half of the flour mixture into the batter and beat for 1 minute on low speed.

Stir in the buttermilk and beat for another minute.

Add the remaining flour mixture and beat just until combined. Fold in the cubed peaches.

Divide the batter into 12 muffin pan cups.

Bake for 25-30 minutes, or until inserted toothpick comes out clean.

Cool the cakes in the pan for 5 minutes, then run a knife around the edges to release cakes.

Place a wire rack over the muffin pan and carefully turn the pan upside down to remove the cakes.

Serve the mini cakes warm with a scoop of vanilla ice cream.