Preheat your oven to 325°F (163°C). In a medium bowl, combine graham cracker crumbs, sugar, cinnamon, and melted butter. Stir until the mixture resembles wet sand. Line a muffin tin with paper liners and evenly press the crust mixture into the bottom of each liner. Chill the crust in the refrigerator for about 10 minutes while preparing the cheesecake filling.

In a large mixing bowl, beat the softened cream cheese and granulated sugar using an electric mixer until smooth and creamy, about 2-3 minutes. Gradually add vanilla extract, flour, and egg, mixing on low speed until just combined. Be careful not to overmix.

Peel, core, and dice Golden Delicious apples into small chunks. In a separate bowl, toss the diced apples with lemon juice, brown sugar, cinnamon, nutmeg, and cornstarch until well coated.

Take your chilled crusts from the refrigerator and spoon the creamy cheesecake filling into each muffin liner, filling them about halfway. Spoon the prepared apple mixture over the cheesecake layer.

In a small bowl, combine oats, flour, brown sugar, and chilled butter. Use your fingers or a fork to mix until the ingredients form a crumbly texture. Sprinkle this streusel topping generously over the apple layers.

Place the muffin tin in the preheated oven and bake for 28-30 minutes, or until the edges are set and the centers jiggle slightly.

Let the cheesecakes cool in the muffin tin for about 30 minutes, then transfer to the refrigerator and chill for at least 2 hours.