**Prepare the Crust**

Preheat oven to 325°F (163°C). In a bowl, mix the graham cracker crumbs, sugar, cinnamon, and melted butter until combined. Press the mixture into the bottom of a greased 9-inch springform pan. Bake for 8-10 minutes, then let cool.

**Make the Cheesecake Filling**

In a large mixing bowl, beat the softened cream cheese and sugar until smooth. Add the eggs one at a time, mixing after each addition. Stir in the vanilla extract, sour cream, and flour. Pour the filling over the cooled crust and smooth the top.

**Bake the Cheesecake**

Wrap the bottom of the springform pan with aluminum foil and place it in a larger baking dish. Fill the dish with hot water about halfway up the sides of the pan to create a water bath. Bake at 325°F (163°C) for 50-55 minutes, or until the center is slightly jiggly but set. Turn off the oven and leave the cheesecake inside with the door slightly open for 1 hour. Then, transfer it to the refrigerator to chill for at least 4 hours (preferably overnight).

**Prepare the Apple Topping**

In a saucepan over medium heat, melt the butter and stir in the diced apples, brown sugar, cinnamon, nutmeg, and lemon juice. Cook for 5-7 minutes, until the apples are soft and caramelized. Remove from heat and let cool.

**Make the Oat Streusel**

In a bowl, mix the flour, oats, brown sugar, and cinnamon. Stir in the melted butter until crumbly. Spread the mixture on a lined baking sheet and bake at 350°F (175°C) for 10-12 minutes, until golden brown. Let cool.

**Assemble the Cheesecake**

Once the cheesecake is fully chilled, spread the caramelized apples over the top, followed by the oat streusel.

**Serve**

Slice and serve with whipped cream or caramel drizzle for an extra indulgent touch!