Grilled Atlantic Flounder Recipe

Preheat and dry fillets

Preheat a grill or grill pan to medium-high (about 400°F / 200°C). Pat the flounder fillets dry with paper towels to remove surface moisture so they sear rather than steam.

Season both sides of each fillet with kosher salt, black pepper and lemon zest. Brush lightly with olive oil to prevent sticking and promote browning. Let sit at room temperature for 10 minutes while you prepare toppings and sauce.

Oil the grill grates or grill pan lightly. Place fillets on the hot grill, flesh-side down. Grill 2–3 minutes without moving until grill marks form and the fish is opaque about two-thirds of the way up. Flip carefully with a thin spatula and grill another 1–2 minutes until just cooked through (fish should flake easily and internal temperature about 135–140°F / 57–60°C). Remove to a warm plate.

While the grill is heating (or in a small skillet while fillets rest), melt 3 tbs unsalted butter over medium heat. Add the minced garlic and cook 20–30 seconds until fragrant but not brown.

Add the breadcrumbs to the skillet and toast, stirring constantly, until golden and crisp, about 2–3 minutes. Remove from heat and stir in chopped parsley, lemon juice, salt and pepper. Taste and adjust seasoning. Keep warm; topping can be made ahead and gently reheated.

When ready to serve, spoon a thin layer of the warm buttery crumbs over each cooked fillet so they sit on top without overwhelming the delicate fish.

In a small saucepan set over medium heat, combine the minced shallots, dry white wine and white wine vinegar. Bring to a gentle simmer and reduce until about 2 tablespoons of liquid remain (this concentrates flavor) — approximately 6–8 minutes.

Optional: add 2 tsp heavy cream and simmer 30 seconds (this helps stabilize the emulsion). Reduce heat to low.

Remove pan from heat. Begin whisking in the cold butter pieces a few pieces at a time, whisking constantly so each piece emulsifies into the reduced wine, creating a smooth glossy sauce. Continue until all butter is incorporated and sauce is thickened (should coat the back of a spoon). If sauce gets too hot and separates, remove from heat and whisk in a splash of cold water or a few ice cubes to bring temperature down, then continue adding butter slowly.

Stir in lemon juice, season with 1/2 tsp salt and 1/4 tsp white or black pepper. Keep sauce warm in a thermos or over the lowest possible heat (set pan in a warm water bath) until ready to serve. Stir in chopped chives or tarragon just before plating for freshness.

Place each grilled flounder fillet on warm plates. Spoon 1–2 tbs of beurre blanc beside or gently over the fillet, then mound 1–2 tbs of the buttered breadcrumb mixture on top of the fish.

Garnish with extra parsley, a sprinkle of chives or tarragon, and a lemon wedge. Serve immediately so the topping remains slightly crisp and the sauce is warm.