Classic Tiramisu with Espresso and Mascarpone

Brew 1.5 cups (360 ml) of strong espresso and let it cool to room temperature, then stir in the dark rum and set aside in a shallow dish.

Separate the eggs carefully, placing yolks in a heatproof bowl and whites in a spotlessly clean bowl for whipping later.

Whisk the yolks with half the sugar over a pot of barely simmering water until pale, thick and ribbony, about 4-5 minutes: the mixture should reach 160°F (71°C) for food safety.

Remove from the heat and whisk in the mascarpone one spoonful at a time until perfectly smooth and glossy, with no lumps remaining.

In a separate bowl, whip the egg whites with the remaining sugar to stiff, shiny peaks that hold their shape when the whisk is lifted.

Fold the whites into the mascarpone mixture in three additions, using a gentle bottom-up motion to preserve the airy texture.

Quickly dip each ladyfinger into the espresso for just 1 second per side: they should be moist but not soggy: and arrange in a single layer in a 9x9 inch (23x23 cm) dish.

Spread half the mascarpone cream over the ladyfingers, then repeat with a second layer of dipped ladyfingers and the remaining cream, smoothing the top.

Cover and refrigerate for at least 6 hours, ideally overnight, to allow the flavours to meld and the texture to set.

Just before serving, dust generously with unsweetened cocoa powder through a fine sieve for a velvety finish.