Preheat oven to 350°F (177°C).
Use a food processor or blender to grind the Biscoff cookies into fine crumbs. You can also place them in a zip-top bag and crush them into fine crumbs using a rolling pin and some arm muscle. In a medium bowl, stir the Biscoff crumbs and melted butter together until combined. The mixture will be thick, coarse, and sandy. Try to smash/break up any large chunks. Pour the mixture into an ungreased 9-inch pie dish. With medium pressure using your hand, pat the crumbs down into the bottom and up the sides to make a compact crust. Do not pack down with heavy force because that makes the crust too hard. Simply pat down until the mixture is no longer crumby/crumbly. Tips: You can use a small flat-bottomed measuring cup to help press down the bottom crust and smooth out the surface, but do not pack down too hard. And run a spoon around the bottom “corner” where the edge and bottom meet to help make a rounded crust this helps prevent the crust from falling apart. For more shaping technique tips, see the Biscoff pie crust recipe page. Bake the crust for 10 minutes. Make the filling in the next step as the crust bakes.
In a large bowl, using a handheld or stand mixer fitted with a paddle attachment, beat the cream cheese and brown sugar together on medium-high speed until the mixture is smooth and creamy, about 3 minutes. Scrape down the sides and up the bottom of the bowl with a silicone spatula as needed. Add the pumpkin, cornstarch, heavy cream, vanilla extract, lemon juice, and spices, and then beat until fully combined and very smooth. Scrape down the sides and up the bottom of the bowl with a silicone spatula as needed to combine you don’t want any lumps. Then on medium speed, add the eggs one at a time, beating after each addition until just blended. After the second egg is incorporated into the batter, stop mixing. If you still see some lumps at this point, switch to a whisk and whisk by hand just until you break up the large lumps. Some small lumps are OK. Reduce the oven temperature to 325°F (163°C). Spread the pumpkin cheesecake filling into the warm crust.
Bake the pie for 40–45 minutes or until the filling is *almost* fully set with a little wobble in the very center. Give the pie a light tap to check. During bake time, if the pie is browning too quickly on top and around the edges, tent with aluminum foil.
Set the pie on a wire rack and cool for 1 hour at room temperature. Then place it in the refrigerator and chill for at least 2 hours and up to 2 days before serving. (Cover if chilling it for longer than a few hours.)
Feel free to garnish the pie with any of the optional toppings listed in the Notes right before or a couple hours before serving. For the pictured pie, I used a piping bag fitted with Ateco 849 piping tip and piped whipped cream in a zigzag pattern around the chilled pie. For neat slices, use a clean sharp knife, and wipe the knife clean after each cut.
Cover and store leftover pie in the refrigerator for up to 5 days.
