Bring a large pot of salted water to a rolling boil. Add the pasta and cook for 8-10 minutes until just al dente. Drain and set aside, reserving a small cup of pasta water.
While the pasta cooks, peel and devein the shrimp if needed. Pat them dry with paper towels and season lightly with salt.
Heat the large skillet over medium heat. Add the olive oil and let it shimmer before adding the shrimp in a single layer. Sauté for 2-3 minutes per side until they turn pink and are just cooked through. Remove the shrimp and set aside.
Reduce the heat to medium-low. Add the butter to the skillet and let it melt gently until bubbling softly. Add the sliced garlic and sauté for about 30 seconds until fragrant, stirring constantly to prevent burning.
Return the cooked shrimp to the skillet, tossing them in the garlic butter sauce for about a minute to rewarm and coat evenly.
Add the drained pasta to the skillet, tossing everything together. If the mixture looks dry, splash in some reserved pasta water a tablespoon at a time until the sauce coats the noodles glossy and smooth.
Squeeze the juice of half a lemon over the pasta, then sprinkle with chopped parsley. Toss gently to combine, and cook for another minute to let the flavors meld.
Transfer the pasta to warm plates, garnishing with extra parsley if desired. Serve immediately while hot and fragrant, enjoying the rich aroma of garlic and butter with every bite.
