1. Bring a large pot of salted water to a boil and cook the spaghetti until al dente. Reserve 1/4 cup pasta water, then drain the pasta.

2. Pat the shrimp dry and season with salt and black pepper.

3. Heat the olive oil and 2 tablespoons of butter in a large skillet over medium-high heat.

4. Add the shrimp in a single layer and cook for 1 to 2 minutes per side, until pink and lightly golden. Transfer the shrimp to a plate.

5. Reduce the heat to medium and add the remaining 2 tablespoons butter to the skillet.

6. Stir in the garlic and cook for 30 seconds, just until fragrant.

7. Add the lemon zest and lemon juice, stirring to combine.

8. Add the drained spaghetti to the skillet and toss well in the lemon butter mixture.

9. Sprinkle in the Parmesan cheese and add the reserved pasta water a little at a time until the pasta looks silky and lightly coated.

10. Return the shrimp to the skillet and toss gently to warm through.

11. Finish with chopped parsley and serve immediately.