If you don't have an ice-cream maker this is an easy, rich and
velvety alternative. Be sure to toast the almonds thoroughly -
their nuttiness is a wonderful contrast to the rich chocolate
cream. Start this recipe a day ahead.
Preheat oven to 190C, and butter and line base and sides of an 8cm x 8cm x 23cm loaf tin with plastic wrap, leaving some overhang.
Roast almonds on an oven tray until golden (10-14 minutes). Cool, then coarsely chop.
Whisk eggs and sugar in a heatproof bowl until pale. Meanwhile, bring milk and vanilla bean and seeds just to the boil in a saucepan over high heat. Add to egg mixture, whisking continuously until combined, return to saucepan and stir continuously over medium heat until mixture thickly coats the spoon (3-4 minutes). Remove from heat, add chocolate and stand for 2 minutes to melt, then stir until smooth. Transfer to a bowl placed over iced water to cool (20-25 minutes).
Whisk cream in a bowl until soft peaks form, then gently fold into chocolate mixture in 3 batches. Fold in almonds, pour into prepared mould, cover with overhanging plastic wrap and freeze until firm (6 hours or overnight). Serve thickly sliced. Semifreddo is best eaten the same week it’s made.