Citrus Semifreddo

Directions

1. 1
   Spray a 9x5x3 inch metal loaf pan with nonstick cooking spray.
2. 2
   Line the pan with plastic wrap, allowing the excess to hang over the ends and sides.
3. 3
   Whisk 1/2 cup of the sugar, the egg yolks, lemon juice, lime juice, limoncello, and salt in a large metal bowl to blend. Stir in the zests.
4. 4
   Set the bowl over a saucepan of simmering water, making sure the bowl doesn't touch the water.
5. 5
   Whisk the egg mixture until it is thick and creamy, and a thermometer inserted into the mixture registers 160*F, about 5 minutes.
6. 6
   Set the bowl of custard into another bowl of ice water to cool completely.
7. 7
   Using an electric mixer, beat the cream and the remaining 1/4 cup sugar in another large bowl until firm peaks form.
8. 8
   Using a large rubber spatula, gently fold the whipped cream mixture into the custard.
9. 9
   Spoon the mixture into the prepared loaf pan.
10. 10
    Fold the overhanging plastic wrap over the custard and freeze until frozen, at least 8 hours or up to 3 days.
11. 11
    Unfold the plastic wrap.
12. 12
    Invert the semifreddo onto a platter and peel of the plastic wrap.
13. 13
    Cut the semifreddo into 1-inch slices, sprinkle with cookie crumbs and serve.