Bring a large pot of water to a roaring boil. Season with 1 teaspoon kosher salt. Add the fettuccine and cook according to the length of time suggested on the package. Stir immediately after adding it to the water and frequently while it is boiling.
Preheat your oven to 350 degrees. Spray two large squares of aluminum foil with cooking spray.
Place a piece of salmon on each piece of foil. Add a little olive oil to each filet and season lightly with salt and pepper.
Fold up the foil in half towards itself and fold down several times. Now fold the ends in towards the top of the packet. Place the packets on a rimmed baking sheet and bake for 14 to 16 minutes or until the salmon registers 140 degrees. When you push down on the salmon with a fork, it should flake easily.
Remove the salmon from the foil and flake into small pieces. Set aside.
While the salmon is baking, in a skillet over medium heat, whisk together the heavy cream and the butter until the butter is melted. Bring it to a simmer, and turn the heat down low. Cook for 15 minutes, stirring occassionally. You should see small bubbles.
Stir in the Parmesan cheese until it melts. Season with salt and pepper, tasting and adding more as needed. We typically add about 3/4 teaspoon salt and almost 1/4 teaspoon black pepper. The seasoning at the end really pulls together the dish, so be sure to play with this.
Toss with fettuccine and salmon and enjoy immediately.