Rinse the prawns under cold water and pat very dry with paper towels. If not already done, peel and devein them leaving tails on or off as you prefer. Drying is important to get a good sear.

Season the prawns evenly with 1 tsp kosher salt, 1 tsp freshly ground black pepper and 1/4 tsp smoked paprika (if using). Toss to coat.

Sauce & Aromatics

Slice aromatics

Trim root ends of the green onions and slice thinly on a diagonal; separate the white and pale-green parts from the bright green tops. Finely mince the garlic (6 cloves).

Heat pan and brown shrimp

Heat a large skillet (10–12-inch) over medium-high heat until hot. Add 1 tbsp olive oil and 1 tbsp butter. When the butter foams and the pan is hot, add the prawns in a single layer without crowding. Cook for 1.5–2 minutes on the first side until golden and opaque about halfway up the sides, then flip and cook another 30–60 seconds until just cooked through. Remove prawns to a plate and set aside.

Make garlic-butter sauce

Reduce heat to medium. Add remaining 2 tbsp butter to the same pan. Add the white and pale-green parts of the sliced green onions and cook 30–45 seconds until softened. Add the minced garlic and cook, stirring constantly, for 20–30 seconds until fragrant but not browned.

Add 2 tbsp dry white wine (or chicken broth) to deglaze the pan, scraping up any browned bits. Let the liquid reduce by about half, ~1 minute. Stir in 1 tbsp fresh lemon juice.

Finish & Serve

Combine and finish

Return the cooked prawns and any accumulated juices to the pan. Toss to coat in the garlic-butter sauce and warm through for 30–60 seconds. Taste and adjust seasoning with a pinch more salt or black pepper if needed. Sprinkle in 2 tbsp chopped parsley, the bright green sliced tops of the scallions, and 1/4 tsp red pepper flakes if using; toss once to combine.

Serve

Transfer to a warmed serving dish. Serve immediately with lemon wedges for squeezing over the prawns. This is excellent over steamed rice, pasta, crusty bread, or as an appetizer.