Preheat oven to 350°F and spray an 8-inch baking pan with baking spray.
To make the apple topping, toss sliced apples with lemon juice, then the brown sugar and cinnamon. Set aside.
To make the cobbler, whisk together the melted butter, brown sugar, milk, vanilla, and salt in a large bowl. Add flour, cinnamon, add baking powder. Whisk until ingredients are incorporated. Spread batter into the prepared pan.
Pour apples and any juices over the top of the batter. Arrange apples in a mostly single layer over the batter.
Bake for 22 to 25 minutes, or until edges are golden brown and center is set. Or until a toothpick inserted into the center of the cake part of the cobbler comes out clean.
Let the cobbler cool; serve warm with ice cream.