Step 1

Bring a large pot of salted water to a boil.  Once the water reaches a rolling boil, add the fettuccine. Gently stir the pasta occasionally to prevent it from sticking together.Boil until al dente (about 1 minute less than the package directions call for). Reserve 1 cup of pasta water, and remove pasta from the heat.

Step 2

For optional peas:Add about 1" of water to a saucepan. Bring to a boil and add the peas. Cover the pan and turn off the heat. Drain after about 4 minutes, or when the peas are tender.Alternatively, simply thaw the peas before using. Do not attempt to cook the peas by adding to the salty pasta water, because it will dehydrate the peas.

Step 3

Flake the salmon apart with a fork. Set aside.If the fillet has skin, discard it.

Step 4

In a large, deep fry pan or a heavy-bottomed pot, melt the butter over medium-low heat. Add the salt.When the butter is melted (but not browned) add the garlic and cook 1-2 minutes, or until the garlic sizzles.

Step 5

Add the cream and bring to a simmer. Continue simmering about 3 minutes, or until the butter has completely incorporated into the cream. There should be no "oily" butter spots left, and the cream will be a pale yellow color.Turn off the heat and whisk in the Parmesan. Continue whisking until the cheese melts into the sauce.Tip: The butter and cream sauce must be piping hot when the cheese is added, otherwise the cheese will not melt. If you paused your cooking for any reason in between adding the cream and butter, reheat the cream before proceeding.

Step 6

Add the pasta and ¼ cup of reserved pasta water to cheese sauce and toss to incorporate.  (Tongs work well for tossing fettuccine.) At first, it will seem like there is too much sauce. As you continue to toss the pasta, the sauce will begin to cling to the noodles. When there is no sauce (or almost no sauce) pooled on the bottom of the noodles, you're done tossing.If the sauce seems dry or stringy, add another splash of the reserved pasta water.  (I usually add at least one splash of pasta water, sometimes two, when cooking this meal.)Tip: If you forgot to reserve pasta water, add a splash of cream, milk or white wine to the sauce instead (not tap water).

Step 7

Add the peas and flaked salmon to the pasta. Toss the pasta. Add black pepper to taste.Serve immediately, making sure to evenly distribute the peas and salmon when serving. If desired, add extra grated Parmesan after plating.