Preheat your oven to 350°F (175°C). In a food processor, crush Biscoff cookies into fine crumbs, then mix with melted butter until it resembles wet sand. Press this mixture firmly into the bottom of a greased 9" springform pan, creating an even layer. Chill the crust in the refrigerator for about 15 minutes to set while you prepare the topping.

In a mixing bowl, combine rolled oats, flour, brown sugar, and melted butter, mixing until crumbly. Set aside to cool at room temperature while you prepare the apple filling.

In a medium saucepan over medium heat, add sliced tart apples, brown sugar, cinnamon, and cornstarch. Cook for about 8–10 minutes or until the apples become tender and syrupy. Remove from heat and allow to cool.

Set your oven temperature to 325°F (163°C) to ensure even baking.

In a large bowl, beat the softened cream cheese with granulated sugar until smooth. Gradually incorporate Greek yogurt, vanilla extract, and spices, mixing until combined. Add eggs one at a time.

Pour the cheesecake batter over the chilled crust, smoothing into an even layer. Spoon the cooled apple mixture over the batter, spreading gently. Sprinkle the crumble topping over the apples.

Bake for 65-70 minutes, until slightly jiggly in the center. A gentle jiggle indicates it's perfectly baked.

Allow the cheesecake to cool to room temperature, then refrigerate for at least 6 hours or overnight to set.