1-Preheat oven to 350°F: Preheat oven to 350°F. Spray a 9×13-inch baking dish with nonstick cooking spray. Set aside.
2-In a large bowl, combine flour, brown: In a large bowl, combine flour, brown sugar, oats, cinnamon, baking powder, and baking soda.
3-Pour melted butter over the mixture and: Pour melted butter over the mixture and mix together until crumbly.
4-Measure out 2 cups of the mixture,: Measure out 2 cups of the mixture, and set aside to reserve for topping.
5-Pour the remaining mixture into the prepared: Pour the remaining mixture into the prepared baking dish. Press firmly to the bottom of the pan.
6-Bake 18-20 minutes, or until golden brown: Bake 18-20 minutes, or until golden brown.
7-In a large bowl, add cream cheese,: In a large bowl, add cream cheese, sugar, and vanilla. Mix with a hand mixer on medium speed until smooth and creamy.
8-With the mixer on low, add the: With the mixer on low, add the eggs, one at a time, until fully incorporated into the mixture. Set aside.
9-In a large bowl, combine apples, flour,: In a large bowl, combine apples, flour, brown sugar, and cinnamon.
10-Arrange the apple mixture evenly on top: Arrange the apple mixture evenly on top of the cooked crust.
11-Spread cream cheese mixture evenly over the: Spread cream cheese mixture evenly over the top of the apples.
12-Crumble the reserved oat mixture over the: Crumble the reserved oat mixture over the top. Bake for 40-45 minutes, or until golden brown.
13-Let come to room temperature before placing: Let come to room temperature before placing in the refrigerator to chill.
14-Drizzle with caramel topping when you are: Drizzle with caramel topping when you are ready to serve (optional).