Follow packet instructions to cook pasta till al dente, reserve pasta water.
Cut salmon into bite sized cubes, place into a bowl and coat with all the marinade ingredients.
In a pan, on low-medium heat, melt butter and add a splash of olive oil.
Add onion and garlic and sauté till translucent and golden, approximately 7-10 minutes.
Add plain flour and cook a further 2 minutes, this is called a roux and will thicken the sauce.
Add milk, heavy cream, freshly grated Parmesan cheese, salt, pepper and dried oregano, then stir continuously until thickened.
Once thickened, add cooked pasta and ladle in a large spoon of reserved pasta water (add more if necessary, till you get to your desired creaminess)
In a separate pan, add olive oil and cook salmon for 2-3 minutes per side.
Serve pasta with salmon on top and garnish with chopped herbs.