Preheat the oven to 350°F and lightly grease a 9x13 inch pan with cooking spray.
In a saucepan, combine brown sugar, water, cornstarch, lemon juice, vanilla, cinnamon, nutmeg, and salt. Stir in the apples and cook over medium heat for 3-5 minutes, stirring occasionally.
Pour the apple mixture into the prepared pan.
In a large bowl, mix together the flour, sugar, baking powder, and salt. Stir in the milk and melted butter until just combined.
Pour the batter over the apples in the pan. Lightly sprinkle with cinnamon.
Bake for 38-40 minutes, or until a toothpick inserted into the topping comes out clean.
Let the cobbler cool for at least 15 minutes before serving. Serve warm, with vanilla ice cream if desired.
Store leftovers covered in the refrigerator for up to 4 days.