01 - Bring a large pot of salted water to a boil. Cook the pasta according to package instructions until al dente. Reserve 1/2 cup of pasta cooking water, then drain.
02 - Pat shrimp dry and season evenly with salt and pepper.
03 - Heat 2 tablespoons of olive oil in a large skillet over medium-high heat. Add shrimp in a single layer and cook for 1–2 minutes per side until pink and opaque. Transfer to a plate and set aside.
04 - In the same skillet, add the remaining olive oil, shallot, and garlic. Cook for 1–2 minutes until fragrant. Stir in crushed red pepper flakes and lemon zest briefly.
05 - Return shrimp to the skillet. Add lemon juice and butter, stirring until butter melts and ingredients meld.
06 - Add drained pasta to the skillet and toss to coat evenly. Incorporate reserved pasta water as necessary to achieve a smooth, silky sauce.
07 - Remove from heat. Stir in Parmesan cheese and fresh parsley. Adjust seasoning with additional salt, pepper, and lemon juice to taste.
08 - Plate immediately, garnishing with extra Parmesan and parsley if desired.