Flounder Moutarde – Simple Elegant Seafood Recipe

What We Sous Vided For Dinner Last Night

Flounder Moutarde isn’t just fish for dinner—it’s flaky, tender perfection dressed in a bold, tangy mustard sauce. Fancy name, surprisingly simple execution. Why serve bland seafood when you can plate up something that tastes straight out of a French bistro? Go on, give your weeknight a little culinary swagger. 🐟

Why This Recipe Works

Flounder Moutarde is delicate and quick to cook, and the mustard cream sauce adds bold flavor without overpowering the fish. Broiling ensures the fillets stay moist while giving just a touch of golden color on top.

Flounder à la Moutarde: Elegant French Fish Made Easy

Looking for a simple, flavorful seafood dish that feels fancy but won’t keep you in the kitchen all night? This Flounder à la Moutarde (flounder with mustard sauce) is flaky, delicate fillets baked under a creamy, tangy mustard sauce that’s rich without being heavy. The mustard gives a lively kick, while a touch of cream smooths everything out beautifully.

Perfect for a weeknight dinner or a dinner party, this recipe comes together in minutes and cooks quickly. Serve it with roasted potatoes, steamed asparagus, or a crisp salad for a restaurant-style meal that’s effortless at home.

Whether you’re a mustard fan or just looking to shake up your seafood routine, this Flounder à la Moutarde will become a repeat favorite.

Common Cooking Mistakes to Avoid

Overcooking the flounder — it cooks very quickly, so watch it closely.
Using too much mustard — a little goes a long way; balance with cream.
Skipping seasoning — a pinch of salt and pepper enhances both the fish and sauce.
Not preheating the oven — broiling works best when the oven is hot.
Adding cream too early — stir in cream off the heat to avoid curdling.

Print Recipe

Flounder Fillets a la Moutarde Recipe

Flounder à la Moutarde: delicate broiled flounder fillets topped with a creamy, tangy mustard-parsley sauce, ready in minutes.

Prep Time15

Cook Time3

Total Time18

Course: Main Course

Cuisine: American, French

Keyword: flounder, French sauce

Servings: people

Equipment

Medium Bowl
baking sheet

Ingredients

8 small skinless, boneless flounder fillets, about 1¼ pounds
salt & pepper to taste
1 tablespoon peanut oil vegetable or corn oil
2 tablespoons mayonnaise preferably homemade
1 tablespoon imported mustard such as Dijon or Dusseldorf
2 teaspoons parsley finely chopped
4 lemon wedges

US Customary - Metric

Instructions

Prep the Fish & Oven

Remove the flounder fillets from the refrigerator to bring them closer to room temperature.
Adjust the top oven rack so the fish is 3–4 inches from the broiler. This prevents overcooking or uneven browning.
Tip: Don’t move the rack after the oven is hot — it’s safer and avoids burns.

Mix the Mustard Sauce

In a medium bowl, combine mayonnaise, mustard, and chopped parsley. Stir until smooth.
Tip: Homemade mayo adds extra flavor, but store-bought works fine too.

Prepare the Baking Sheet

Lightly oil a baking sheet to prevent sticking.
Arrange the flounder fillets evenly on the sheet.
Tip: Use a silicone baking mat if you have one — cleanup is easier, and the fish won’t stick.

Brush the Sauce Onto the Fillets

Evenly coat each fillet with the mayo-mustard-parsley mixture.
Make sure each piece is fully covered for a golden, flavorful top.

Broil the Fish

Place the baking sheet 3–4 inches from the broiler.
Broil 2–3 minutes, watching carefully — the fish should be just cooked through and the topping golden brown.
Tip: Thicker fillets may take closer to 3 minutes; thinner fillets may only need 1–2. Keep an eye on them.

Serve Immediately

Serve the flounder with roasted potatoes, rice, or your favorite vegetables.
Don’t forget the lemon wedges for a bright finishing touch.
Tip: A quick squeeze of lemon right before eating enhances the mustard flavor beautifully.

Side Dish Suggestions

Side Dish	Why It Works
Steamed Asparagus	Its mild, grassy flavor balances the richness of the mustard-cream sauce.
Buttered New Potatoes	Creamy and earthy, these potatoes soak up the sauce and add comforting texture.
Garlic Green Beans	Adds a crisp, fresh contrast to the tender fish and tangy sauce.
Lemon Rice Pilaf	The citrus notes brighten the dish and pair naturally with seafood.
Crusty French Bread	Perfect for sopping up the mustard sauce—simple and satisfying.
Celery Root Purée	A silky, slightly sweet base that complements the sharpness of the mustard.
Mixed Greens Salad	Light and peppery greens (like arugula) cleanse the palate and keep things fresh.
Ratatouille	Adds color, heartiness, and French flair to the plate without overpowering it.
Sauteed Spinach	Soft and earthy, it absorbs sauce nicely and keeps the plate balanced.
Couscous	Light, fluffy, and quick—ideal for soaking up flavors without stealing the show.

Here’s my big old fluke fillet. Well I think it’s fluke and not flounder. Be sure to take it out of the refrigerator in advance of cooking so you’re not sticking a cold piece of fish under the broiler.

Here’s my mayo, mustard and parsley mixture to spread all over the fish.

After placing the fish on a roasting pan, season it with salt and pepper to taste. Spread the mayonnaise, mustard, and parsley coating on top of the fish.