Bring a large pot of salted water to a rolling boil and cook the pasta until just shy of al dente, about 8 minutes. Drain, reserving a splash of pasta water, and set aside.
While the pasta cooks, heat olive oil in a large skillet over medium heat. Add minced garlic and cook for about 30 seconds until fragrant, with a slight sizzle, but not browned.
Add the shrimp to the skillet, season lightly with salt and pepper, and cook for 2-3 minutes per side until they turn bright pink, opaque, and slightly curled. Remove the shrimp with a slotted spoon and set aside.
Immediately add the fresh basil leaves to the same skillet, gently bruising them with the back of a spoon or your fingers to release their aroma. Stir quickly for about 15 seconds until fragrant but not wilted.
Return the cooked shrimp to the skillet, then add the drained pasta. Squeeze in the lemon juice and toss everything together until the pasta is coated and heated through, about 1 minute. If the sauce seems dry, add a splash of reserved pasta water to loosen it and help it cling to the noodles.
Sprinkle red pepper flakes over the pasta, give it a final toss, and taste. Adjust seasoning with more salt, pepper, or lemon juice if needed. Serve immediately, garnished with additional basil if desired.
