01 - Preheat oven to 325°F. Line a 12-cup muffin tin with paper liners.
02 - In a bowl, combine graham cracker crumbs, sugar, and melted butter until evenly moistened. Divide mixture among liners and press firmly into bottoms.
03 - Bake crusts for 5 minutes until set. Remove from oven and let cool while preparing filling.
04 - Beat softened cream cheese in a large bowl until completely smooth. Add sugar and mix until well incorporated. Add eggs one at a time, beating thoroughly after each addition. Blend in vanilla extract and sour cream until smooth and combined.
05 - Spoon cheesecake batter over cooled crusts, filling each liner about three-quarters full. Bake for 18 to 20 minutes until centers are just set but still slightly jiggly. Cool completely in the pan, then refrigerate for at least 2 hours until firm.
06 - Melt butter in a skillet over medium heat. Add diced apples, brown sugar, granulated sugar, cinnamon, nutmeg, lemon juice, and salt. Cook, stirring occasionally, for 4 to 6 minutes until apples are tender but not mushy.
07 - Stir oats and flour into the apple mixture. Cook for an additional 2 to 3 minutes, stirring frequently, until the mixture becomes crumbly and lightly golden. Remove from heat and let cool completely.
08 - Top each chilled cheesecake with a generous spoonful of the apple crisp topping. Serve chilled or bring to room temperature for 15 minutes before serving.