Preheat oven to 350°F. Pour melted butter into 9x13 glass dish. Set aside. In a large saucepan, mix together peaches, sugar and lemon juice on medium heat. The mixture should simmer for about 5-10 minutes until the peaches are softened.
In a large bowl, combine flour, sugar, milk and vanilla for batter.
Pour the peach mixture into the glass dish, then pour the batter on top in an even layer. Bake 35-45 minutes, until the top looks firm.
Sprinkle sugar on top in an even layer, then put back in the oven with the broiler on high. It should only take a couple of minutes for the sugar to caramelize and the top to turn golden brown. Keep the oven light on and watch it so it doesn't burn. It will turn golden really fast!
Serve warm with some ice cream.