Preheat your oven to 350°F (175°C).
Prepare the apples: Peel, core, and slice the apples, then toss them with sugar, lemon juice, and cinnamon.
Spread the apple mixture evenly into a greased baking dish.
In a separate bowl, whisk together flour, baking powder, salt, melted butter, and milk to create the batter.
Pour the batter over the apples, spreading it out gently.
Bake for 40-45 minutes, or until the topping is golden brown and a toothpick inserted into the center comes out clean.
Let cool for at least 10 minutes before serving.
Serve warm with vanilla ice cream or whipped cream if desired.