Brew coffee in a regular coffee maker or press pot. This should yield one cup of coffee.

In a small saucepan, add the brewed coffee and sugar and bring to a boil

Allow to thicken.

Add dark rum.

Remove from heat place in shallow dish and set aside.

In a double boiler, place yolks and sugar.

Beat constantly over a low flame until the sugar has dissolved, the colour of yolks has lightened and the volume of the mixture has doubled.

Place the bowl over an ice bath and allow to cool completely.

In a clean large bowl, whip the heavy cream with a whisk until soft peaks are formed. Set aside.

Fold the mascarpone into the egg yolk mixture.

Gently fold the whipped cream into the mascarpone and egg yolk mixture.

Add vanilla essence.

Dip the essential Waitrose rich highland shortie biscuits into the coffee liqueur and arrange one layer at the base of a glass baking dish.

Pour a thick layer of tiramisu cream over the soaked biscuits.

Repeat until the tiramisu cream reaches the top of the rim.

Sift cocoa powder onto the top of the tiramisu.

Place in freezer or refrigerator, and allow to set for at least 4 hours.

Cut into squares and serve.