Fill a large pot with water. Salt the water generously and set it over medium-high heat. We'll need this ready for boiling our pasta.
Now, sprinkle the shrimp with kosher salt on both sides. In a large skillet set over medium heat, add the olive oil (or oil from the sundried tomatoes). When the oil is warm, add the shrimp in one even layer. Cook on each side for about 1-2 minutes. Remove from the skillet and set aside.
Add in a few more teaspoons of olive oil, if needed. Add in the minced shallot and garlic. Cook until softened, about 1-2 minutes. Then add in the tomato paste, Calabrian chili and sundried tomatoes. Cook, stirring occasionally for 1-2 minutes.
Add the chicken broth and heavy cream, stirring and gently scraping up bits from the pan. Bring to a gentle simmer. Cook on low heat for about 8 minutes until the sauce has thickened and coats the back of the spoon. Give it a taste and adjust the salt if needed, I added about ¼ teaspoon.
To the pot of boiling water, drop in the spaghetti and cook until al dente.
Use tongs to carefully transfer the pasta directly from the pot to the sauce, we want some residual water from the pasta. Then add the parmesan along with the spinach and butter. Toss everything together until combined. Add the shrimp back to the pot to heat through.
Divide pasta amongst bowls. Then garnish with grated parmesan and chopped parsley.
