Preheat the oven to 350°F.

Prepare the peach topping by slicing the peaches and combining them with brown sugar and butter in a skillet over medium heat until caramelized.

In a mixing bowl, combine all-purpose flour, granulated sugar, baking powder, and salt.

In another bowl, whisk together milk, egg, and vanilla extract.

Combine the wet and dry ingredients, mixing until just combined.

Pour the batter over the caramelized peaches in the skillet.

Bake for about 25 minutes, or until golden brown and cooked through.

Allow to cool slightly before inverting onto a serving plate.