Step 1: Prepare the filling

1. In a large bowl, beat the heavy cream with a hand or stand mixer until soft peaks form.
2. In another bowl, combine the mascarpone cheese, powdered sugar, and vanilla extract. Mix until smooth and creamy.
3. Gently fold the whipped cream into the mascarpone mixture until fully combined.

Step 2: Prepare the coffee mixture

1. In a shallow bowl, mix the cooled coffee with the Biscoff spread (if using) until smooth.

Step 3: Assemble the tiramisu

1. Dip each Biscoff cookie into the coffee mixture for 1-2 seconds, ensuring it’s coated but not soggy.
2. Arrange a single layer of dipped cookies at the bottom of a 9×9-inch dish or similar serving dish.
3. Spread half of the mascarpone filling over the cookie layer, smoothing it with a spatula.
4. Repeat with another layer of dipped cookies and the remaining mascarpone filling.

Step 4: Add the topping

1. Sprinkle the top of the tiramisu with crushed Biscoff cookies and a dusting of cinnamon or cocoa powder.

Step 5: Chill and serve

1. Cover the dish with plastic wrap and refrigerate for at least 4 hours, or overnight for best results.
2. Slice and serve chilled.