Italian "English soup" - trifle with two custards (Zuppa inglese)

1. Bring the milk to the boil with the lemon zest; in a bowl, whisk the egg yolks with the sugar and flour until smooth, then pour in the hot milk while whisking, return to the pan and cook, stirring, until thick.

2. Divide the custard between two bowls: stir the chopped dark chocolate into one half straight away until melted, and leave the other half as a yellow lemon custard; cover both with cling film and let cool.

3. Mix the alkermes liqueur with the water and sugar.

4. Line the base of a glass dish of about 20x30 cm with a layer of ladyfingers, dipping each one quickly in the alkermes liquid (don't let them go soggy), and spread over half the yellow custard.

5. Add another layer of dipped ladyfingers, then the chocolate custard, then more ladyfingers and the remaining yellow custard; drizzle any leftover chocolate custard on top.

6. Chill for at least 4 hours (ideally overnight) and dust with cocoa powder before serving.

Tip: A dessert from Emilia-Romagna and Tuscany; the bright red alkermes gives it its typical colour and aroma - if you can't find it, use rum, or sour cherry syrup for children; it keeps for 2 days in the fridge.