Stuffed Flounder with Tomatoes, Roasted Red Peppers, and Olives

Flounder fillets are too thin to stuff the way you might a piece of salmon, by cutting a slit in the side, but they’re perfect for rolling around a savory filling. The filling infuses the delicate fish with flavor, and, after baking, the fish retains its shape and holds onto the savory stuffing for a beautiful presentation.

This stuffed flounder looks and tastes like a meal that takes a lot more time and effort than it does. It’s quick enough for a weeknight meal, but elegant enough for a weekend treat. With its mild, delicate flavor, flounder wins over even those who think they don’t like fish. I make extra filling on purpose, since it doubles as a bright, briny relish you’ll keep going back for.

What is in Stuffed Flounder?

This stuffed flounder recipe relies on flavorful ingredients without overpowering the delicate flavor of flounder. Here’s what you’ll need:

• Flounder fillets: A flat fish, flounder’s thin fillets are perfect for rolling around a flavorful filling. If some are too narrow, you can double them up, overlapping them slightly, to accommodate more filling.
• Shallots: Mellower than onions, but with a flavor closer to garlic, shallots add sweet and savory complexity without overwhelming the fish.
• Grape tomatoes have a sweet, rich flavor, and their small size makes them ideal for the filling. Cooking them quickly on the stove concentrates their flavor even more.
• Roasted red peppers add a sweet and smoky flavor to the filling. Use the jarred ones or make your own. 
• Castelvetrano olives: Mild and buttery green Castelvetrano olives add a mellow brininess to the sauce without overpowering the other flavors. You can use another type of pitted olives, if you like. 
• Fresh dill is aromatic and bright, lifting the flavors of the filling and the flounder. 
• Chicken stock adds richness and depth to the pan sauce and keeps the fish moist while baking. You can substitute seafood stock or vegetable broth.
• White wine brings fruity acidity to the pan sauce and prevents the fish from drying out in the oven. To make this dish alcohol-free, replace the wine with more stock or a mix of stock and lemon juice.
• Garlic infuses the pan sauce and the flounder with its irresistibly sweet, nutty flavor.
• Saffron: A small pinch of saffron brings floral complexity to the sauce and adds an attractive golden color.
  • READ MORE: See our full guide to buying, preparing, and storing saffron.
  • TRY IT: Saffron grown high in Morocco’s Atlas Mountains
• Extra virgin olive oil adds richness to the filling. I like the mild, buttery flavor of Italian Nocellara, which is another name for Castelvetrano olives.
  • READ MORE: Cooking with Olive Oil: Everything You Need to Know
  • TRY IT: Italian Nocellara Extra Virgin Olive Oil from Sicily
• Kosher salt and black pepper enhance the other flavors of the dish.

How to Make Stuffed Flounder

Stuffed flounder looks and tastes more elaborate than it is. The filling needs just 5 minutes on the stove to concentrate flavors, and then the stuffed fish bakes to perfection in 15 to minutes. Here’s how to make it:

• Get ready. Arrange a rack in the middle of the oven and preheat to 375°F.
• Make the filling. Heat 1 tablespoon of olive oil in a skillet over medium-high heat. Add the 1 large or 2 small diced shallots, 3/4 cup quartered grape tomatoes, and 1/2 cup chopped roasted red peppers. Cook for about 5 minutes, stirring occasionally, until the tomatoes begin to burst and the shallots have softened. Take the pan off the heat and stir in 1/4 cup roughly chopped Castelvetrano olives and 1 tablespoon chopped fresh dill. Season to taste with salt and black pepper.
• Stuff the fish. Lay the flounder fillets on a clean work surface. Season both sides of the fish with salt and pepper. Spoon 3 to 4 tablespoons of the filling on top of each filet. There will be extra stuffing leftover. Working with one filet at a time, roll the fish around the filling and place it seam-side-down in a 9×9-inch or 11×7-inch baking dish.
• Bake the fish. Add 1/4 cup chicken stock, 1/4 cup white wine, 2 cloves minced garlic, and a small pinch of saffron threads to the pan. Bake for 15 to 20 minutes or until the fish is flaky and cooked through.
• Serve. Serve the stuffed flounder with the extra filling, spoon the pan sauce over the fish, and garnish with more chopped fresh dill.

Make It Your Own

This weeknight fish dish is highly versatile. Here are a few ideas for swaps and substitutions to customize it to your taste. 

• Substitute another flat fish: Swap the flounder for another flat fish like fluke, sole, or halibut. If your halibut fillets are thick and meaty, consider cutting a slit in the middle and adding the filling using this method, rather than wrapping the fish around it. You can also make this dish with tilapia fillets.
• Make it brinier: Swap the buttery Castelvetrano olives for punchier kalamata olives, or use 2 tablespoons chopped Castelvetrano olives and 2 tablespoons capers.
• Swap the herbs: Replace the dill with another fresh herb like basil, tarragon, or parsley. Or use a mix of herbs.
• Make it lemony: Omit the white wine from the pan sauce. Increase the stock to 1/3 cup and add 2 tablespoons lemon juice. Serve the stuffed flounder with lemon wedges. This is a great swap if you want to omit the alcohol.

What to Serve with Stuffed Flounder

I could eat a whole baguette by dipping it in the pan sauce and topping it with the extra stuffing, but other starches work just as well for soaking up the saffron sauce. For a quick and simple weeknight meal, serve it with steamed rice or roasted potatoes. For something a little more special on the weekend, make this lemony spinach couscous.

While the flounder is already stuffed with vegetables, a side of greens just feels right with this dish. Try flavorful braised greens, like Greek horta, or crisp and tender roasted broccoli.