Pat the shrimp dry with paper towels. Season lightly with salt and pepper.
Melt 2 tablespoons of butter in a large skillet over medium-high heat.
Add the shrimp to the skillet in a single layer. Cook for 1 to 2 minutes per side until pink and opaque. Do not overcrowd the pan; cook in batches if necessary. Remove the cooked shrimp and set aside.
Reduce the heat to medium. Add the remaining 2 tablespoons of butter to the skillet.
Add the minced garlic and red pepper flakes (if using). Cook for about 30 seconds until fragrant, being careful not to burn the garlic.
Pour in the white wine or broth and let it simmer for 1 minute, scraping up any browned bits from the bottom of the pan.
Stir in the lemon juice.
Return the cooked shrimp to the skillet. Toss gently to coat with the sauce.
Remove from heat immediately. Stir in the fresh parsley. Serve right away.
Notes
For best results, do not overcook the shrimp; they cook very fast. Remove them from the heat as soon as they turn pink.
Serve this shrimp over pasta, rice, or alongside steamed asparagus for a complete meal.
If you prefer a richer sauce, substitute half the wine/broth with heavy cream.