Begin by bringing a large pot of salted water to a rapid boil. Once boiling, add the spaghetti and cook according to the package instructions until it reaches an al dente texture. Once done, drain it, toss it with a little olive oil to prevent sticking, and set aside.

In a large skillet heated over medium-high heat, add 2 tablespoons of butter and the olive oil. Season the jumbo scallops with kosher salt and freshly ground black pepper. Sear the scallops for about 3–4 minutes per side until they are golden brown and caramelized. Once done, remove them from the skillet and set aside.

In the same skillet, melt the remaining 2 tablespoons of butter. Add the diced onion and cook until it becomes soft and translucent, roughly 3–4 minutes. Stir in the minced garlic and let it cook for about 30 seconds to release its aroma.

Pour in the savory chicken broth and heavy cream, stirring to combine. Bring the mixture to a gentle simmer. Once simmering, add the cornstarch slurry and cook until the sauce thickens.

Stir in the roughly chopped spinach and sun-dried tomatoes. Season generously with salt and black pepper. Let it simmer briefly until the spinach wilts.

Reduce the heat to low and return the seared scallops to the skillet, gently coating them in the rich sauce. Add the cooked spaghetti, tossing everything together until well combined.

Transfer the pasta to a serving dish, sprinkle with freshly chopped parsley, and serve immediately while hot.