Wrap the bottom of a 9-inch springform pan in aluminum foil and preheat the oven to 350°F.

In a mixing bowl, combine 4 tablespoons of cold unsalted butter, 3/4 cup packed brown sugar, 3/4 cup all-purpose flour, and 1 teaspoon of pumpkin pie spice. Mix until crumbly and chill.

Mix together 1/2 cup brown sugar and 1 tablespoon pumpkin pie spice in a small bowl for the filling.

Pulse 46 Biscoff cookies in a food processor to powder, then mix with 6 tablespoons melted butter and 1 tablespoon granulated sugar. Press into the prepared springform pan and bake for 15 minutes.

In a stand mixer, beat 24 ounces of softened cream cheese with 1 1/4 cups granulated sugar and 1/4 cup cornstarch until smooth. Gradually add in the other filling ingredients.

Spread half of the cheesecake batter over the cooled crust, sprinkle the spiced brown sugar filling, add the remaining batter, and top with streusel.

Place the springform pan in a roasting pan and pour boiling water around it. Bake for 1.5 hours, then let sit in the oven for an hour.

Cool the cheesecake at room temperature for about an hour, then refrigerate for at least 8 hours before serving.

Beat 3/4 cup heavy cream with 1/4 cup powdered sugar until stiff peaks form. Serve on the cheesecake.