Do not overmix the filling. Whisk only until it is smooth. Air beaten into a baked cheesecake makes it rise, sink and crack, and this one is meant to be dense.
Take it out while the middle still wobbles. A set centre in the oven is an overbaked centre on the plate. It carries on firming as it cools and then again in the fridge.
The chilling times are minimums. An hour out and an hour in the fridge will get you there; overnight is better, and it slices far more cleanly cold.
Pour the melted Biscoff over a cold cake. Warm and it soaks in and runs off the sides instead of setting into a layer.