Line a loaf pan with plastic wrap or parchment paper, leaving 3 inches of overhang on each side. Use an electric mixer to beat the cream in a large bowl until it holds soft peaks. Refrigerate.
Fill a saucepan with 2 inches of water and bring it to a simmer over medium heat, adjusting the heat if necessary to keep the water from boiling. Meanwhile, whisk together the egg yolks and 1/2 cup of the sugar in a large heatproof bowl until smooth. Set the bowl over the simmering water and use an electric mixer to beat the mixture until it is thick and fluffy, 4 to 5 minutes. Remove from the heat and keep beating until it’s pale yellow and has roughly doubled in volume. Set aside; wash the beaters.
In a separate heatproof bowl set over the simmering water, beat together the egg whites and remaining 1/4 cup sugar until fluffy, then remove the bowl from the heat and continue beating until the whites hold stiff peaks.
Purée the strawberries in a blender or food processor (with a little water if necessary to get the machine going) until smooth; strain. Gently fold the egg whites into the yolk mixture until just combined, then fold in the whipped cream followed by the strawberry purée. Transfer the mixture to the prepared loaf pan and press the overhanging plastic wrap over the surface. Freeze until firm, at least 8 hours and up to 3 days. To serve, use the plastic wrap to lift the semifreddo and transfer it to a plate. Discard the plastic wrap and cut into slices.
Peach-Vanilla Semifreddo Peel, pit, and chop 2 large ripe peaches; substitute these for the straw- berries. Add 1 tablespoon vanilla extract to the cream before whipping.
Pistachio-Cardamom Semifreddo Pulse 1 cup unsalted pistachios in a food processor until coarsely chopped. Cook the egg yolk mixture with 1/2 teaspoon cardamom; beat the cream with 1/2 teaspoon almond extract. Fold in the nuts just before freezing.
Chocolate Semifreddo Melt 4 ounces of dark chocolate in the microwave or in a separate bowl over the simmering water and whisk it into the cooked egg yolk mixture. Fold 2 ounces chopped chocolate into the mixture before freezing.
Espresso-White Chocolate Semifreddo Cook 1/2 cup freshly brewed espresso with the egg yolks and sugar. Melt 4 ounces white chocolate in the microwave or in a separate bowl over the simmering water and fold it into the cooked egg yolk mixture before freezing.
Peanut Butter Semifreddo Of course you can use any nut butter here. Warm 3/4 cup peanut butter in the microwave or in a small saucepan, then whisk it into the whipped egg yolk mixture.
Two-Tone Semifreddo Make any two of the pre-ceding variations by dividing the egg yolk mixture equally between two bowls, halving the additions in the variations, and folding half of the beaten egg whites and whipped cream into each bowl. Pour one into the loaf pan, smooth it out, and pour the other on top. Freeze as directed.
Semifreddo Pie An excellent pie for the summer: Pulse graham crackers, gingersnaps, sugar cookies, chocolate wafers, or any crisp cookie in a food processor to make 1 cup fine crumbs. Add 1 tablespoon melted butter and press into the bottom of the loaf pan before topping with semifreddo. Or double the crust and use a springform pan.