In a mixing bowl, combine graham cracker crumbs, ½ teaspoon cinnamon, and sugar. Pour in the melted butter and stir until everything is well moistened. Firmly press this mixture into the bottoms of 9 paper cupcake liners using a flat measuring cup for an even layer. Once shaped, place the lined cups in the refrigerator to chill for about 15 minutes while you prepare the topping.

In a separate bowl, whisk together all-purpose flour, quick-cooking oats, light brown sugar, and the remaining cinnamon. Drizzle in melted butter and mix until you achieve a crumbly texture.

In a large mixing bowl, toss the diced apples with lemon juice, light brown sugar, and additional cinnamon. Allow the mixture to sit for about 5 minutes to let the flavors meld together.

Using a large mixing bowl, beat the cream cheese until smooth. Gradually add sugar, flour, and vanilla extract, mixing until well combined. Blend in the egg just until incorporated.

Preheat the oven to 325°F (160°C). Spoon the cheesecake batter over the chilled graham cracker crusts until they are about two-thirds full. Layer the apple mixture on top of the batter and add the streusel topping over the apples.

Place the assembled mini cheesecakes in the preheated oven and bake for 28-30 minutes until the edges are set but the centers jiggle slightly.

Once baked, cool at room temperature for 30 minutes, then transfer to the refrigerator to chill for at least 2 hours. Drizzle with caramel sauce before serving.