Preheat the oven to 350°F and grease a 9×13 inch pan lightly with cooking spray.
Stir together brown sugar, water, cornstarch, lemon juice, vanilla, cinnamon, nutmeg, and salt together in a saucepan. Stir in apples. Cook over medium heat for 3-5 minutes, stirring.
Pour mixture into prepared pan.
In a large bowl mix together the flour, sugar, baking powder, and salt. Stir in the milk and melted butter, just until combined.
Pour the mixture over the apples in the pan. Sprinkle lightly with cinnamon.
Bake for about 38-40 minutes or until a toothpick inserted into the topping comes out clean.
Allow to cool for at least 15 minutes before serving. Serve warm with vanilla ice cream, if desired.
Cover and store leftovers in the refrigerator for up to 4 days.
Make Ahead:You could prepare the apple filling and store it in the fridge for up to 3 days, or freeze it for up to 3 months.You can also freeze the baked cobbler for up to 3 months. Thaw overnight in the refrigerator and warm in the oven before serving.