Preheat oven to 350°F.
To make the batter, whisk together the flour, sugar, baking powder, and salt in a bowl.
Add the milk to the dry mixture and whisk to combine to make the batter.
Pour the melted butter into a 9 x 13-inch pan and move the pan around so that the bottom and sides of the pan are covered with butter.
Pour the batter over the butter. Do not stir them together.
To make the topping, combine the peaches, vanilla, lemon juice, cinnamon, and sugar in a large bowl and gently stir with a rubber spatula.
Drop the peach mixture by spoonfuls onto the batter. Again, do not stir the two together.
Bake for 1 hour or until golden brown.
Serve warm or cold, alone, or with whipped cream, or my favorite, vanilla ice cream.