Preheat the oven to 350°F (175°C). In a baking dish, spread the sliced peaches evenly.

In a mixing bowl, combine self-rising flour, milk, and sugar until smooth. Pour the melted butter into the baking dish over the peaches, then pour the batter evenly over the top.

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