In a large saucepan of boiling salted water, cook pasta until al dente.
Meanwhile, in a small nonstick skillet, melt half the butter over medium.
Add garlic and pinch of red-pepper flakes; cook until fragrant, 1 minute.
Raise heat to medium-high; add wine. Cook until reduced by ⅓, about 1 minute.
Add shrimp and season with salt and pepper; cook until opaque throughout, 1 to 2 minutes.
Remove skillet from heat; swirl in lemon juice and remaining butter.
Add pasta and toss to combine.
Serve topped with parsley.
