Follow these steps to create your Biscoff Speculoos Tiramisu:

1. Prepare the Coffee: Brew your favorite coffee and allow it to cool to room temperature.
2. Whip the Cream: In a large mixing bowl, whip the heavy cream until soft peaks form. Gradually add the powdered sugar and vanilla extract, continuing to whip until stiff peaks form.
3. Mix the Mascarpone: In another bowl, gently mix the mascarpone cheese until smooth.
4. Combine Mixtures: Carefully fold the whipped cream into the mascarpone mixture. Be gentle to maintain the light and airy texture.
5. Prepare the Cookies: Pour the cooled coffee into a shallow dish. Dip each Biscoff cookie briefly into the coffee, ensuring they soak but do not become soggy.
6. Layer the Ingredients: In a rectangular dish, start by placing a layer of dipped Biscoff cookies at the bottom.
7. Add Cream Layer: Spread half of the mascarpone cream mixture over the cookie layer.
8. Repeat Layers: Add another layer of dipped Biscoff cookies, then top with the remaining mascarpone mixture.
9. Finish with Cocoa: Lightly sift cocoa powder over the top layer of mascarpone.
10. Chill: Cover the dish with plastic wrap and refrigerate for at least 4 hours, ideally overnight, to allow the flavors to meld.

Following these steps will lead you to a beautifully layered Biscoff Speculoos Tiramisu that is both delicious and visually striking.