Italian Semifreddo (No-Churn Frozen Mousse Dessert)

Line a loaf mold generously with plastic wrap, leaving overhang for unmolding later.

Put 4 egg yolks in a mixing bowl, then add 80 g sugar and 40 ml water to a small saucepan.

Bring the sugar water to a boil, then keep it over medium heat until it reaches 118°C.

When the bubbles become smaller and tighter, remove the pan from the heat immediately to avoid overcooking.

Whisk the yolks continuously while pouring the hot syrup in a thin stream.

Aim the syrup down the side of the bowl so it blends smoothly and does not cook the yolks into small lumps.

Keep whipping for about 5 minutes, until the sabayon turns pale, thick, and airy.

Let it cool completely before adding cream, because warm sabayon can melt the whipped cream and collapse the texture.

Whip 300 ml heavy cream with 1 teaspoon vanilla to soft-medium peaks, about 70 percent whipped.

Fold it into the cooled sabayon in two additions, then gently fold in 40 g chopped pistachio.

Pour the mixture into the prepared mold and level the surface.

Freeze for at least 6 hours, then rest it at room temperature for 5 to 10 minutes before unmolding and slicing cleanly.