Preheat oven to 350°F (175°C).
Prepare peaches: In a bowl, toss peaches with ½ cup sugar, cinnamon, and lemon juice. Set aside.
Make batter: In another bowl, whisk together flour, remaining sugar, baking powder, salt, and milk until smooth.
Butter the dish: Pour melted butter into a 9x13-inch baking dish. Do not stir.
Assemble: Pour the batter over the butter, then spoon peaches evenly on top. Do not mix.
Bake for 40–45 minutes, until the crust is golden brown and bubbly.
Serve warm with vanilla ice cream, whipped cream, or a drizzle of heavy cream.