Add the coffee powder into a medium sized bowl and stir in 180ml (¾ cup) of just boiled water. Stir the sugar and Marsala wine into the coffee. Allow the coffee mixture to cool to room temperature.

Separate the egg yolks and egg whites into two large bowls. Although you only want to use 3 of the egg whites so discard the fourth (or save for another purpose).

In the bowl with the egg yolks, add the sugar. Whisk until the mixture changes from a deep yellow to a pale yellow and becomes thick and ribbony.

Add the mascarpone cheese and vanilla extract to the egg yolk mixture. Use an electric hand-held whisk to mix until smooth and only just combined. It should only take about 20-30 seconds.

In the bowl with the egg whites, use a clean, dry whisk or beaters to whip the egg whites until stiff peaks form.

Gently fold the whipped egg whites into the mascarpone mixture. Be careful not to deflate the egg whites too much.

Continue folding until the mixture is smooth.

To assemble the tiramisu, quickly dip each ladyfinger into the cooled coffee mixture, making sure not to oversaturate. Arrange a layer of dipped ladyfingers in the bottom of a 9x9 inch serving dish.

Spread a third of the mascarpone mixture (about 225g) over the ladyfingers.

Repeat the layering process, creating three layers of ladyfingers and three layers of mascarpone cream.

Press down lightly on each layer to ensure even distribution.

Cover the tiramisu with plastic wrap and refrigerate overnight or for at least 8 hours to allow the flavours to meld and the dessert to set.

Just before serving dust the top layer with cocoa powder.

Use a sharp knife to cut and serve chilled portions.