**Prepare the Crust**
- Preheat oven to 350°F (175°C). Line a 9x13-inch baking pan with parchment paper.
- In a mixing bowl, combine graham cracker crumbs, melted butter, and sugar. Mix well, then press evenly into the bottom of the prepared pan.
- Bake for 8-10 minutes. Let cool while preparing the filling.
**Make the Cheesecake Layer**
- In a large mixing bowl, beat the softened cream cheese and sugar until smooth.
- Add the eggs one at a time, mixing well after each addition. Stir in vanilla extract.
- Pour the cheesecake mixture over the cooled crust and spread evenly.
**Prepare the Apple Layer**
- In a separate bowl, toss the diced apples with sugar, cinnamon, and nutmeg.
- Evenly distribute the spiced apples over the cheesecake layer.
**Make the Streusel Topping**
- In another bowl, mix the flour, oats, brown sugar, cinnamon, and melted butter until crumbly.
- Sprinkle the streusel evenly over the apples.
**Bake the Bars**
- Bake for 35-40 minutes, or until the cheesecake layer is set and the streusel topping is golden brown.
- Remove from oven and let cool at room temperature for 30 minutes, then refrigerate for at least 2 hours before slicing.
**Add the Caramel Drizzle**
- Before serving, drizzle with caramel sauce for the perfect finishing touch.