Espresso Tiramisu with Dark Rum

Ingredients

• 300 ml strong espresso coffee, cooled
• 3 tbsp dark rum
• 200 g sponge finger biscuits
• 4 egg yolks
• 100 g caster sugar
• 500 g mascarpone
• 300 ml double cream
• 30 g dark chocolate, finely grated
• 2 tsp cocoa powder, for dusting

Method

1. Stir the cooled espresso and dark rum together in a shallow bowl wide enough to fit a sponge finger lying flat. Make sure the coffee is properly cooled — warm coffee turns the biscuits to mush in seconds.
2. In a large bowl, beat the egg yolks, caster sugar and a pinch of fine salt with an electric whisk for 4–5 minutes, until pale, thick and tripled in volume. You're looking for the ribbon stage — when you lift the whisk, the mixture should fall back on itself in slow, glossy ribbons that hold for a few seconds. The salt is doing quiet work here, lifting the coffee and chocolate notes that come later.
3. Add the mascarpone and beat on low for 30 seconds, just until smooth — push it any harder and the mascarpone splits into a grainy mess you can't bring back. In a separate bowl, whip the double cream to soft, billowy peaks that flop gently when you lift the whisk, not stiff. Fold it into the mascarpone mixture in two additions, cutting down through the middle and turning up from the bottom — you want to keep every bit of air you've built.
4. Taste the cream now. It should taste rich and just-sweet, with the salt sitting underneath rather than announcing itself. Adjust with another tiny pinch if it tastes flat — fix it now, not at the table.
5. Working quickly, dip each sponge finger into the espresso mixture for 1–2 seconds per side — soaked through but still holding their shape. Any longer and they collapse on the way to the dish. Lay them in a single tight layer in the base of a large dish or across individual glasses.
6. Spread half the mascarpone cream over the biscuits in generous swoops, then scatter over half the grated dark chocolate. Repeat with another layer of soaked biscuits and the remaining cream, smoothing the top with the back of a spoon.
7. Cover and refrigerate for at least 4 hours, ideally overnight. The biscuits drink in the coffee, the cream sets to a sliceable softness, and the rum mellows into the background.
8. To serve, dust the top generously with cocoa powder through a fine sieve, then scatter over the remaining grated dark chocolate so it glints against the cocoa. Bring the whole dish to the table and spoon straight from it.