First cut the onions and leeks into fine rings and finely grate the garlic. Sweat the onions in a little butter until translucent, add the leek and continue to sauté until the consistency is nice and soft. Salt the mixture only lightly (the salmon brings extra salt), pepper and season with nutmeg. Mix the sour cream with the flour and two eggs and 200g grated cheese. Cut the salmon into small pieces, cut the spring onions into rings and then mix this with the cream mixture. Add the leek and onion mixture, mix everything well and season again if necessary. Cut small squares out of the puff pastry, place them in molds and fill them with the mixture, then press down lightly on top. Brush with the yolk of the remaining ice cream and sprinkle with the remaining cheese. Then bake as instructed.