Preheat your oven to 375°F (190°C).
In a medium bowl, combine the sliced peaches and 1/2 cup of sugar. Let sit for 10 minutes.
Pour the melted butter into a 9x13-inch baking dish.
In another bowl, whisk together the flour, remaining sugar, baking powder, and salt.
Stir in the milk until the batter is smooth.
Pour the batter over the melted butter in the baking dish. Do not stir.
Spoon the peach mixture evenly over the batter. Sprinkle with cinnamon if desired.
Bake in the preheated oven for 40-45 minutes, or until the topping is golden brown and set.
Let cool slightly before serving. Serve warm with a scoop of vanilla ice cream if desired.