In a mixing bowl, combine finely crushed graham cracker crumbs, melted unsalted butter, and brown sugar until well mixed. Press this into the bottom of a 9-inch springform pan and bake at 325°F for 10 minutes.

In a separate bowl, beat softened cream cheese with a mixer until smooth. Gradually add sugar, sour cream, and vanilla, mixing until combined. Incorporate eggs one at a time on low speed.

Pour the cheesecake filling over the cooled crust, smoothing the top with a spatula.

Place the springform pan in a larger baking dish and fill the outer pan with hot water halfway up the sides.

Bake the cheesecake at 325°F for 60 to 70 minutes until slightly jiggly in the center. Turn off the oven and crack the door to cool for 1 hour.

Toss diced apples with lemon juice, sugar, cinnamon, nutmeg, and flour in a bowl. Add oats and cubed butter, mixing until crumbly.

Spread the apple mixture on a baking sheet and bake at 350°F for 20 minutes, until tender and golden.

Remove the cheesecake from the water bath and refrigerate for at least 4 hours or overnight.

Spoon the cooled apple crisp topping over the chilled cheesecake and drizzle with caramel sauce before serving.