Preheat the oven at 450F.
Thaw the puff pastry if you are using a store bought one.
Chop the onions and garlic.
In a pan, on low to medium heat, pour the olive oil and sauté the onion for 3-4 minutes then add the garlic.
Wash the spinach leaves, chop them and add them to the onions. Toss for a minute or 2.
Add the cream to the pan and stir well. Season with salt and pepper according to taste.
Pour the creamy preparation in an oven safe dish.
Place the 4 pieces of salmon on top of it.
Cover with the puff pastry and seal well on the edges.
Bake for 25 minutes. Serve and enjoy!