Preheat the oven to 325°F (160°C).
Prepare a muffin tin with cupcake liners.
In a large bowl, beat the cream cheese and granulated sugar until smooth.
Add the vanilla extract and sour cream, then mix until combined.
Add the egg and mix until just combined.
In a separate bowl, combine the diced apples, cinnamon, and a splash of lemon juice.
Distribute the cheesecake mixture evenly into the prepared muffin tin.
Top each cheesecake with the prepared apples.
In another bowl, mix together oats, flour, brown sugar, and melted butter.
Sprinkle the oat mixture over the top of each mini cheesecake.
Bake for 20-25 minutes or until the edges are set and the centers are slightly jiggly.
Allow the cheesecakes to cool in the tin for 10 minutes, then transfer to a wire rack.
Chill the cheesecakes in the refrigerator for at least 2 hours before serving.
