Preheat the oven to 350°F (175°C).
In a medium bowl, mix graham cracker crumbs and melted butter.
Press the mixture into the bottom of a lined muffin tin to form the crust.
In a large mixing bowl, beat the softened cream cheese and sugar until smooth.
Add the eggs one at a time, mixing well after each addition.
Stir in the vanilla extract.
Spoon the cheesecake mixture over the prepared crust in the muffin tin.
In a separate bowl, combine diced apples, cinnamon, brown sugar, and oats.
Distribute the apple mixture evenly on top of the cheesecake layers.
Bake for 25-30 minutes until the filling is set and the tops are lightly golden.
Allow the mini cheesecakes to cool before removing them from the muffin tin.
Once cooled, refrigerate for at least 2 hours before serving.