Finely dice onion and garlic, sauté in butter, add spinach and 5 tablespoons of water, cover and defrost over medium heat. Then drain the spinach in a sieve and squeeze out well.
Dice the salmon. Coarsely grate the cheese. Quarter the cherry tomatoes.
Mix the salmon, spinach, cheese and crème fraîche. Season well with salt, pepper and nutmeg.
Preheat the oven with a tray on the lowest rail to 220 °. Do not use circulating air.
Remove the dough from the packaging and divide it into triangles at the perforations. Now place a circle made up of the triangles on a sheet of baking paper (40 x 30). The broad ends of the triangles must be about halfway on top of each other. Spread the spinach mixture in a bead on the circle so that about 1 cm remains free to the inner edge. Now fold the tips inwards over the mass and fold under the wreath and press down a little.
Use the parchment paper to pull the wreath onto the hot baking sheet. Bake in the oven on the lowest rack for 25 minutes, cover with aluminum foil after 15 minutes.