Wash the spinach in plenty of cold water and change the water 2-3 times. Sand and other unwanted substances can be easily removed by washing and moving the spinach several times in water. Place the leaf spinach on a sieve and drain.
Peel shallots and garlic clove and finely dice them. Please use a sharp knife and do not chop the ingredients. Sweat the shallots and garlic cubes in a large pot with the butter for a few minutes until translucent.
Place the spinach in the pot and cook with the lid on high heat for 2-3 minutes until the spinach has collapsed. Add the cream and bring to the boil once, season with salt, pepper, cayenne pepper and nutmeg and leave to stand next to the stove without lid.
Season the salmon fillet with salt and pepper and fry in a pan on both sides. The salmon should be juicy cooked on the inside, which means briefly roasted and then cooked over a low heat, so that a tender fish fillet comes to the plate. Alternatively, in the article above under point 3, I describe further variants for cooking, poaching or roasting salmon fillets.
Strain the cream sauce through a fine sieve into an extra pot and bring to the boil. Mix the corn starch with a little cold water and add to the boiling cream sauce. Add cold butter and truffle oil to the sauce and mix until foamy.
Arrange the spinach on hot plates, add the salmon fillet and add the foamy cream sauce to the dish. Serve quickly - enjoy your meal!