Put a small mixing bowl in the fridge to chill.
Combine the coffee with the Marsala or other liquor. Put the coffee syrup in a flat baking dish and set it aside while you make the mascarpone layer.
1 cup espresso, ¼ cup Marsala, brandy, or Kahlua
In a medium bowl, combine the mascarpone, Biscoff cookie butter, vanilla, salt, and ½ teaspoon of the cinnamon together until they are well mixed. Set this bowl aside while you whip the whipping cream.
2 cups mascarpone, ½ cup Biscoff cookie butter, 2 tablespoons vanilla extract, 1½ teaspoons cinnamon
Take the small mixing bowl from the fridge and whip the heavy whipping cream in it until it forms stiff peaks.
2 cups heavy whipping cream
Use a spatula to scoop and mix about a quarter of the whipped cream into the mascarpone mixture to lighten it. Then gently fold the remaining whipped cream until you no longer see large pockets of cream or mascarpone.
To construct the Biscoff cookie tiramisu, dip the Biscoff cookies two at a time into the coffee syrup and place them in a single layer in one large or multiple smaller serving dishes as you prefer. Repeat with a second, overlapping layer.
64 Biscoff cookies
Add about half of the Biscoff mascarpone cream, and then gently place another double layer of Biscoff cookies dipped in the coffee syrup on top of that. Finish off with a second layer of Biscoff mascarpone cream.
Combine the cocoa and remaining teaspoon of cinnamon in a small bowl and use it to dust a thin layer on top of the tiramisu.
¼ cup unsweetened cocoa powder, 1½ teaspoons cinnamon
Chill your Biscoff tiramisu for at least 4 to 6 hours, but take it out of the refrigerator for about 15 minutes before serving.