Preheat the combi steam oven to 90 °C. Spray 10 ramekins lightly with oil spray.
Make batter
Beat 250 g cream cheese and ½ cup caster sugar using a stand mixer until smooth. Add 2 tsp cornflour and 2 eggs and mix well. Then add 2 tbsp Biscoff smooth spread, ½ tsp vanilla extract and 250 g sour cream. Beat on low speed until well combined.
Cook cheesecakes
Pour the mixture equally into the prepared ramekins. Place the ramekins in a large perforated tray and cover lightly with a sheet of foil, but do not seal. Place them in the preheated combi steam oven and cook for 18-20 minutes or until just set. Once the cheesecakes are done, remove from the oven and chill in the refrigerator.
Toppings
Meanwhile, place 124 g Biscoff biscuits and 20 g butter into a food processor and pulse until a fine, even crumb is formed. Heat 150 g Biscoff smooth spread in a small pot on induction level 2 and gently heat while stirring until it drizzles from the spoon.Tip: Avoid overheating or the biscoff spread may go grainy.
To serve
Drizzle each cheesecake with a spoonful of the softened Biscoff spread, sprinkle the Biscoff crumble over the top, then add a dollop of whipped cream (if using). Cut 38.75 g Biscoff biscuits in half and place each half on top of each cheesecake.