Preheat your oven to 350°F (175°C).
In a large mixing bowl, combine the sliced peaches, ½ cup of sugar, cinnamon, vanilla extract, and lemon juice. Stir until the peaches are well coated.
Pour the peach mixture into a greased 9x13-inch baking dish.
In another bowl, whisk together the flour, baking powder, salt, and the remaining ½ cup of sugar.
Gradually stir in the milk until the batter is smooth.
Pour the batter evenly over the peach mixture in the baking dish. Do not stir; the batter will rise during baking.
Drizzle the melted butter over the top of the batter.
Sprinkle 1 teaspoon of sugar over the buttered batter for added sweetness and crunch.
Bake in the preheated oven for 40-45 minutes, or until the top is golden brown and a toothpick inserted in the center comes out clean.
Allow to cool for about 10 minutes before serving.