Prep: Melt butter and pour into a 13 x 9-inch casserole dish, set aside. Slice the peaches and set aside.
In a mixing bowl, combine flour, 1 cup sugar, baking powder, and salt. Add milk and stir until dry ingredients are moistened. Pour the batter over the butter in the casserole dish but DO NOT STIR. Butter will remain on the outer edges of the batter.
Bring remaining 1 cup sugar, peach slices, and lemon juice to a boil over high heat, stirring constantly; pour over batter but DO NOT STIR. Sprinkle with cinnamon.
Bake at 375° for 40 to 45 minutes or until golden brown. Serve the peach cobbler warm with a dollop of mascarpone or a scoop of vanilla ice cream.