1. In a large bowl, use an electric mixer to whisk the egg yolks and half of the sugar until it goes a pale yellow and has tripled in volume.
2. In another bowl, whisk together the cream, vanilla and remaining sugar until soft peaks form. Add the mascarpone and whisk again until it is well combined.
3. Gently fold the mascarpone mixture into the egg yolks, making sure that everything is fully combined.
4. Add your coffee and vanilla to a low dish and gently dip the Malt biscuits into the mixture, leaving them for a few seconds to soak up the liquid before placing in a serving dish. Double layer your biscuits along the bottom of the dish before adding a third of the cream mixture. Repeat until you have three double layers of biscuits and top with the final third of the cream mixture.*
5. Dust with cocoa and leave covered in the fridge to chill for at least 3 hours before serving.

*For a more creamy tiramisu, only single layer your biscuits.