Preheat your oven to 325°F (160°C).

In a mixing bowl, combine graham cracker crumbs, 1/4 cup sugar, and melted butter. Mix until crumbly and then press the mixture into the bottom of a 9-inch springform pan.

In a large bowl, beat the softened cream cheese with 1 cup sugar until smooth. Add in the vanilla and eggs one at a time, mixing well after each addition.

Pour half of the cream cheese filling over the crust.

In another bowl, combine the sliced apples with cinnamon and brown sugar; spread this mixture evenly over the cream cheese layer.

Then pour the remaining cream cheese mixture on top.

In a different bowl, mix flour, oats, brown sugar, and melted butter to create the streusel topping. Sprinkle this over the cheesecake.

Bake for about 1 hour, or until set.

Once baked, allow the cheesecake to cool completely before refrigerating for at least 4 hours or overnight prior to serving.