Bring a large pot of salted water to a boil. Cook fettuccine noodles a few minutes shy of al dente, according to package directions. The noodles will finish cooking in the sauce.

Pat salmon filets dry and salt and pepper each side. Heat a large skillet over medium-high heat and add olive oil. Add the salmon filets, skin side down if they have the skin on, and sear for 4 minutes. The salmon should pretty easily lift up when it's ready to flip, if not, give it another minute. Sear on the other side for 3-5 minutes until the internal temperature reaches approximately 145°F. Remove from pan and set aside.

In the same skillet, add butter. Once melted, add the sliced shallots and a pinch of salt; cook for 2-4 minutes until slightly soft. Add minced garlic, a pinch of salt, freshly ground black pepper, and red pepper flakes if using. Cook for 2 minutes, then add the corn kernels and cook for an additional 3-4 minutes. Stir in pesto, milk, and 1/4 cup pasta water, and additional salt to taste; bring to a simmer.

Stir in parmesan cheese and add in the just-before-al-dente noodles; toss to combine, adding additional pasta water as needed to reach the desired consistency of the sauce. Taste test for salt levels, too. Let the noodles cook for an additional 1-2 minutes in the sauce.

Serve with salmon filets or flake the salmon and toss in the pasta.