Prep: Prep your ingredients. Set aside a plate and some foil to keep the cooked shrimp warm. Get a pot of water boiling for the pasta and make a colander ready in the sink for draining. IMPORTANT: Reserve 1/2 cup of cooking water when draining the pasta!
Cook the shrimp: Melt 1 tablespoon butter in a large skillet over medium heat. Add the shrimp and season with salt and pepper. Cook until browned, about 2-3 minutes per side. Set aside on a plate and cover tightly with foil. Wipe the skillet.
Cook the sauce: In the same skillet, melt the remaining butter. Add the garlic and Italian seasoning and cook for 1 minute. Pour in the white wine and chicken stock. Add the lemon zest and simmer for 3 minutes. Stir in the parmesan, cream and parsley and cook for 1 more minute.
Finish the dish: Add the cooked and drained pasta to the skillet and toss. Add the spinach and toss until it's wilted, about 1 minute. Add reserved cooking water, a little at a time, and toss until the sauce is smooth and creamy and coats the pasta well. Toss in the shrimp. Serve ASAP with parmesan, black pepper, chili flakes and lemon juice.