How to Make It
In a medium stainless-steel bowl, whisk the eggs with the sugar and amaretto liqueur. Set the bowl over a large saucepan of simmering water and whisk constantly until the mixture turns bright yellow and thickens, about 10 minutes. Do not let the eggs get too hot or they will scramble. Remove the bowl from the heat and continue whisking for a few minutes to cool the mixture slightly. Set aside and let cool to room temperature, then fold in the amaretti.
In a large stainless-steel bowl, beat the cream to soft peaks. Fold the cream into the egg mixture. Spoon the semifreddo into an airtight container, cover with plastic wrap and freeze until firm, at least 6 hours or up to 5 days.
Remove the semifreddo from the freezer and let stand at room temperature for 5 to 10 minutes to soften slightly. Meanwhile, in a small saucepan, melt the chocolate over low heat, stirring occasionally. Scoop the semifreddo into flutes or parfait glasses, drizzle with the melted chocolate and serve.