Start by zesting the lemon using a citrus zester to capture bright, fragrant strips of peel. Then, juice the lemon and set both zest and juice aside.
Heat your large skillet over medium heat. Add a tablespoon of butter along with a splash of olive oil if desired. Once the butter melts and begins to shimmer, add the sliced garlic and sauté for about 30 seconds, until fragrant and just starting to turn golden.
Add the shrimp in a single layer to the skillet. Cook for 2-3 minutes on one side until they turn pink and start to curl. Flip and cook for another 2 minutes, until fully opaque and firm.
Pour in the white wine or broth and use tongs to gently scrape the bottom of the pan, releasing any flavorful browned bits. Let this simmer for 1-2 minutes until slightly reduced and fragrant.
Add the lemon zest, lemon juice, and remaining butter to the skillet. Swirl or stir gently until the butter melts and coats the shrimp evenly, creating a glossy, flavorful sauce. Sprinkle in red pepper flakes if using.
Turn off the heat and sprinkle the chopped parsley over the shrimp. Give everything a gentle toss to combine and allow the flavors to meld for a minute.
Serve immediately straight from the skillet, garnished with extra parsley if desired. Enjoy this bright, tender shrimp with crusty bread or over your favorite pasta for a complete meal.