Preheat your oven to 350°F (175°C) and grease a muffin tin.
In a bowl, combine melted butter and brown sugar. Stir in sliced peaches and distribute evenly in the muffin tin.
In another bowl, mix flour, granulated sugar, baking powder, and salt. In a separate bowl, whisk together milk, vanilla, and egg. Combine wet and dry ingredients.
Pour the batter over the peaches in the muffin tin. Bake for 25 minutes or until golden brown.
Let cool briefly, then invert the tin to release the mini cakes.
Notes
Serve warm or at room temperature. You can add a scoop of ice cream on top for extra flavor.
Keyword mini cakes, peach dessert, Peach Upside-Down Mini Cakes, upside-down cake