Use fully peeled and deveined shrimp. If frozen, thaw overnight in the fridge — never cook from frozen in a skillet or released water will kill the sear. Pat shrimp completely dry with paper towels. Season with salt just before cooking; add paprika, garlic salt, or red pepper flakes if using. Have lemon, parsley, and butter measured and ready before the shrimp hit the pan — cook time is short.

Heat a large skillet over medium to medium-high heat. Add enough olive oil, butter, or both to coat the pan. For garlic or red pepper flakes, add to the oil first and sauté 1–2 minutes until fragrant — don't let the garlic burn. Once the fat is hot and shimmering, add shrimp in a single layer. Don't crowd the pan or they'll steam instead of sauté — work in batches if needed. Cook without moving for 1.5–2 minutes per side, flipping once. Total time: 2–3 minutes for small shrimp, 4–5 minutes for large. Watch closely — they overcook fast. Optional: add a splash of wine, lemon juice, or broth once shrimp are nearly done. Let reduce about 1 minute. Finish with a squeeze of fresh lemon.

Shrimp are done when opaque and pink with a loose C curl — a tight O means overcooked. USDA target is 145°F, but visual cues are faster and more reliable here. Pull them immediately when the C forms; do not let them sit in the hot pan. Carryover heat will keep cooking them. Finish with fresh parsley and pan juices. Serve right away with rice, pasta, or crusty bread.