While your pasta water comes to a boil, prepare all your ingredients: mince the garlic, dice the onion into 1/4-inch pieces, grate the Parmesan cheese, and chop the sundried tomatoes into bite-sized pieces. Pat the salmon fillets dry with paper towels and season both sides generously with salt and black pepper. Season the shrimp similarly in a separate bowl. Bring a large pot of salted water to a rolling boil and add the pasta, cooking according to package directions until al dente. Reserve 1 cup of pasta water before draining, then set the cooked pasta aside.

Heat 1 tablespoon of olive oil in a large skillet over medium-high heat until it shimmers. Place the seasoned salmon skin-side down and sear for 3-4 minutes without moving it—this creates a beautiful golden crust and renders the fat from the skin. Flip the salmon and cook for just 1 minute more on the flesh side, then transfer it to a plate. In the same pan, add the remaining tablespoon of oil and quickly sear the seasoned shrimp for about 1 minute per side until they turn pink and opaque. Transfer the shrimp to the plate with the salmon. I like to sear the salmon skin-side down first because it keeps the flesh moist while the skin gets crispy.

In the same skillet over medium heat, sauté the diced onion for 2-3 minutes until it begins to soften and become translucent. Add the minced garlic and cook for another 30 seconds, stirring constantly, until fragrant but not browned. Pour in the heavy cream and bring it to a gentle simmer, stirring occasionally. Add the chopped sundried tomatoes and fresh lemon juice, then season with salt and black pepper to taste. Let the sauce simmer for 2-3 minutes to allow the flavors to meld and the cream to thicken slightly.

Add the baby spinach to the simmering cream sauce in batches, stirring gently until each batch wilts into the sauce before adding more. Once all the spinach is incorporated and wilted, gently fold the cooked salmon and shrimp back into the sauce and let everything warm through for about 1 minute. I prefer to add the spinach at the end because it keeps its vibrant green color and fresh flavor better than if it simmered for too long.

Return the cooked pasta to a large bowl or directly to the skillet with the sauce. Add about 1/2 cup of the reserved pasta water to loosen the sauce and create a silky consistency that coats the pasta beautifully. Toss gently to combine everything, adding more pasta water if needed to achieve your desired sauciness. Finish by folding in most of the freshly grated Parmesan cheese, reserving some for garnish. Divide the creamy pasta among serving bowls and top each portion with an extra pinch of Parmesan cheese and a few generous turns of black pepper.