01 - Bring a large pot of salted water to a boil. Cook spaghetti according to package directions until al dente. Reserve 1/2 cup of pasta cooking water, then drain.
02 - Pat shrimp dry with paper towels. Season evenly with salt and black pepper.
03 - In a large skillet over medium heat, melt butter with olive oil. Add minced garlic and sliced chilies, sautéing for 1 to 2 minutes until fragrant without browning.
04 - Add shrimp in a single layer to skillet. Cook 1 to 2 minutes per side until shrimp turn pink and opaque.
05 - Stir in lemon zest and lemon juice, coating the shrimp evenly.
06 - Add drained pasta to the skillet with shrimp and garlic-chili butter. Toss thoroughly to combine. Add reserved pasta water gradually if needed to loosen the sauce.
07 - Stir in chopped parsley. Taste and adjust seasoning with additional salt, pepper, or lemon juice as preferred.
08 - Serve immediately, garnished with extra parsley, grated Parmesan, and lemon wedges if desired.