01 - Bring a large pot of salted water to a rolling boil. Add spaghetti and cook until al dente according to package directions. Reserve 1/2 cup pasta water, then drain the pasta.
02 - Pat shrimp dry with paper towels. Season with salt and freshly ground black pepper evenly.
03 - In a large skillet over medium heat, melt the butter and add olive oil. Incorporate minced garlic and sliced chilies, sautéing for 1 to 2 minutes until fragrant without browning.
04 - Arrange shrimp in a single layer in the skillet. Cook for 1 to 2 minutes on each side until shrimp turn pink and opaque.
05 - Stir in lemon zest and lemon juice to coat the shrimp evenly.
06 - Add drained pasta directly to the skillet and toss it thoroughly with shrimp and garlic-chili butter. Use reserved pasta water gradually to loosen the sauce if necessary.
07 - Stir in chopped parsley. Adjust seasoning with additional salt, black pepper, or lemon juice to taste.
08 - Serve immediately, garnished with extra parsley, grated Parmesan, and lemon wedges if desired.