Preheat the oven to 350°F (175°C). In a mixing bowl, combine sliced peaches, sugar, lemon juice, vanilla extract, and cornstarch. Toss to coat the peaches evenly.

Pour the peach mixture into a greased 9-inch baking dish.

In another bowl, mix flour, sugar, baking powder, and salt. Stir in milk and melted butter until just combined.

Pour the batter over the peach filling. Do not stir.

Bake in the preheated oven for 30-35 minutes or until the topping is golden brown and a toothpick inserted comes out clean.

Let cool for a few minutes before serving.