Place a standard loaf pan into the freezer while you prepare the ingredients.
Chop the pistachios using a food processor. Transfer to a small bowl.
Give the food processor a quick wipe and puree the thawed raspberries. Press the puree through a fine sieve set over a bowl. Discard the seeds/solids. Set the puree aside.
If you use a stand mixer, clean everything well between the next steps. I have a hand mixer with two sets of beaters, so I switched beaters and used separate bowls.
Whip the cream to soft peaks in a large bowl.In a separate bowl, beat the egg yolks, sugar and vanilla until the sugar has dissolved and the yolks lighten in color.Swap out the beaters and whip the egg whites to soft peaks in yet another bowl. Fold the egg yolks and the egg whites into the whipped cream.
Remove the loaf pan from the freezer. Spoon about half the semifreddo mix into the loaf pan. Drizzle half of the raspberry puree over the mix and marble it with the tip of a knife. Sprinkle with half the chopped pistachios.Repeat for another layer.Cover the pan with plastic wrap and then foil.Freeze for at least 6 hours. Before serving allow the semifreddo to soften at room temperature for 15 - 20 minutes. Garnish with chocolate sauce, fresh raspberries and more pistachios.
