To a large bowl, combine the shrimp, 1 tablespoon of the olive oil, 2 cloves of the garlic, and salt. Toss to coat and marinate for 20 minutes.

Heat remaining olive oil in a frying pan over medium heat. When hot, add shrimp and cook 1-2 minutes per side until shrimp are just pink. Remove shrimp with a slotted spoon to leave liquid in the pan. (If cooking from frozen, see note*)

Add the remaining garlic and red pepper flakes to the pan. Cook until fragrant, about 30 seconds.

Add broth and lemon juice. Cook until reduced by half, about 5 minutes.

Add butter and cook until melted and the sauce thickens. Add shrimp back to the pan. Sprinkle with parsley and warm for 1-2 minutes before serving. Serve over pasta or with french bread, if desired.