Salmon Coulibiak

• 3 eggs (plus)
• 1 egg yolk
• 1/2 rice
• 1/2 mushroom-onion mixture
• 3/8 sauce (white)
• 350 gr long rice (grain)
• 300 gr cohoe salmon
• 160 gr puff pastry (frozen)
• 240 ml bechamel sauce (thick)
• 80 gr mushrooms (fresh)