Semifreddo is Italian for "half cold", and can refer to many semi-frozen desserts. This semifreddo straddles several desserts classifications; its mousselike texture is similar to ice cream, but is lighter, airier, and less frozen. I always enjoy ice cream recipes that did not rely on an ice-cream maker, and this one does not. It somehow feels like you've beaten the system, making (a variation of) ice cream without needing "proper" equipment.
Whipped the heavy cream and then gently fold in the egg and nutella mixture. Pour into the prepared loaf tin, and cover with cling wrap before putting it in the freezer for about 4 hours.
When ready to serve, remove from freezer, leave for around 3 minutes for it to thaw, turn out the semifreddo onto a plate, sliced and sprinkle with pistachios.