Peel and coarsely dice the carrots. Boil in salted water for about 10 minutes, drain. Finely dice 1/4 of them and set aside.
Chop the onion and sauté in the hot butter. Puree with the coarsely diced carrots and the cream, stir in the eggs and season with salt, pepper and nutmeg. Pour half of the puree into a greased loaf pan (about 25 cm). Then cover with half of the carrots set aside, and then spread the remaining puree on top. Finally, sprinkle the remaining carrots on top.
Cook in a preheated oven (E-heater 175 degrees, convection oven 150 degrees) in a hot water bath for about 1 hour. Let cool and then turn out, then let cool.
Roast the pine nuts without fat, let cool. Cut the basil into fine strips and arrange on the terrine with the pine nuts, drizzle with a little oil.