Bring a large pot of salted water to a rolling boil, then add the pasta and cook until just al dente, about 8 minutes. Drain, reserving a cup of pasta water.
Meanwhile, heat the olive oil in a large skillet over medium heat until it shimmers gently and releases a fruity aroma.
Add the thinly sliced garlic to the hot oil and sauté for about 30 seconds, until fragrant and just starting to turn golden.
Increase the heat slightly and add the shrimp to the skillet. Cook for 2-3 minutes per side, until they turn pink, opaque, and develop a slight char around the edges.
Sprinkle the red pepper flakes over the shrimp and toss gently to distribute the spice evenly, allowing the flavors to toast briefly in the oil.
Add the drained pasta to the skillet and toss vigorously with tongs, allowing the noodles to soak up the oil, garlic, and shrimp juices. If it looks a bit dry, add a splash of the reserved pasta water to loosen and create a glossy coating.
Squeeze the juice of half the lemon over the pasta and sprinkle chopped parsley on top. Toss again to combine, brightening the dish with citrus and fresh herbs.
Check the seasoning, adjusting salt or lemon as needed. Serve immediately, garnished with extra parsley and a drizzle of olive oil if desired.
