Make the passionfruit curd ahead of time and let it cool completely in the refrigerator. Preheat oven to 350° F and line a cupcake pan with paper liners.
Bake the crust: Combine 1 cup Biscoff crumbs with 2 oz melted butter, stirring until crumbs are thoroughly and evenly hydrated. Add about one tablespoon of mix to each muffin cup, firmly pressing into each liner. Bake for 5 minutes.
Make the cheesecake: Beat 16 oz soft cream cheese in the bowl of a stand mixer with the paddle attachment or with electric beaters until soft and creamy, 1-2 minutes. Add ½ cup sugar; cream until light and fluffy, one additional minute.
Add ⅓ cup sour cream and 3 tbsp passionfruit curd, mixing until just incorporated. Scrape down the sides and bottom of the mixing bowl and give it a quick mix to blend. Beat in the 2 eggs, one at a time, mixing gently on low speed just until combined. Pour or scoop batter into muffin cups, filling them all the way to the top.
Bake until cheesecakes are cooked through, lightly golden on top, and just a tiny bit of jiggle is left in the centers, about 15-20 minutes.
Cool: Allow cheesecakes to cool 10-15 minutes before removing from pan. Then, cool them at room temperature for about another 30 minutes. Finally, chill in the refrigerator for at least 1 hour before serving.
Finish: Once cheesecakes are cold and set, top each with about 1 tbsp passionfruit curd and a little bit of fresh passionfruit pulp, if desired. Serve cold.