Line the quiche tin with puff pastry (do not grease beforehand!). Put the drained tuna, prawns, mussels and the medium-sized diced salmon fillet in a bowl. Chop the onions and herbs and add to the seafood. Mix the eggs, creme fraiche, hollandaise sauce, salt and pepper well and add to the other ingredients. Mix everything carefully but well and then pour the mixture into the mold.
Cut the mozzarella into thin slices or pieces and spread on the quiche. Bake at 200 ° C for about 20 minutes on the middle rack. The cooking time can vary depending on the nature of the oven.