Follow these simple steps to create your Apple Crisp Mini Cheesecakes:

1. Preheat Oven: Preheat your oven to 325°F (160°C). Line a muffin tin with cupcake liners.
2. Make the Crust: In a bowl, mix the crushed graham cracker crumbs, sugar, and melted butter until well combined. Press this mixture into the bottom of each liner to create the crust.
3. Prepare the Cheesecake Mixture: In a large bowl, beat the softened cream cheese with granulated sugar until smooth. Add in the vanilla extract and mix well. Gradually add eggs one at a time, mixing until fully incorporated. Finally, add the sour cream and mix until smooth.
4. Fill the Muffin Tin: Pour the cheesecake batter into each crust-lined cup until filled about ⅔ full.
5. Prepare Apple Topping: In a separate bowl, combine the diced apples, brown sugar, and cinnamon. Mix well and set aside.
6. Make the Crisp Topping: In another bowl, mix the rolled oats, all-purpose flour, and melted butter until crumbly.
7. Assemble the Mini Cheesecakes: Add a tablespoon of the apple mixture on top of each cheesecake layer, followed by a sprinkle of the oat topping.
8. Bake: Place the muffin tin in the preheated oven and bake for 25-30 minutes, or until the center of the cheesecakes is set.
9. Cool: Remove from the oven and let cool in the muffin tin for about 15 minutes. Then, transfer to a wire rack to cool completely.
10. Chill: Once cooled, refrigerate the mini cheesecakes for at least 2 hours before serving to set fully.