Preheat the oven to 350°F (175°C).

In a mixing bowl, combine sliced peaches, 1/2 cup sugar, lemon juice, cornstarch, and cinnamon. Toss to coat the peaches evenly.

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

In another bowl, whisk together flour, remaining sugar, baking powder, and salt.

Add milk and melted butter to the dry ingredients, stirring until just combined.

Pour the batter over the peach mixture in the baking dish, spreading it evenly.

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.