Mix flour, baking powder, salt, ½ cup sugar, and milk together just until all of the lumps are gone.
Melt butter in 9×9 baking dish. Pour the melted butter into batter, but do not stir it in.
Pour peach slices and juice into the baking dish. Sprinkle 1 tablespoon of sugar over the peaches. (Omit the sugar if using peach pie filling instead of canned peaches.)
Pour batter over the peaches. Sprinkle 1 tablespoon of sugar and 2 – 3 teaspoons of cinnamon over the top of the batter.
Bake at 350 degrees for 45 minutes. Crust should be golden brown.
