Baked Flounder with Roasted Tomatoes

Prep Time:
20 mins
Total Time:
30 mins

Here, Dijon mustard serves a dual purpose: It flavors the delicate fish, and helps the breadcrumb coating stay in place as the fish cooks. Tilapia can be used in place of the flounder.


  • 6 plum tomatoes, halved lengthwise

  • 2 tablespoons olive oil, plus more for one of the baking sheets

  • ¾ teaspoon dried tarragon

  • 1 pinch sugar

  • Coarse salt and ground pepper

  • cup mayonnaise

  • 1 tablespoon fresh lemon juice

  • 3 slices white sandwich bread (about 1 ounce each), torn into large pieces

  • 4 flounder fillets (1 ½ pounds total)

  • 2 tablespoons Dijon mustard


  1. Preheat oven to 450, with racks in upper and lower thirds. Place tomatoes on a rimmed baking sheet. Sprinkle with 1 tablespoon oil, 1/4 teaspoon tarragon, sugar, salt, and pepper; toss to coat. Arrange tomatoes cut side up. Roast on lower rack until tender, 20 to 25 minutes. (Keep oven on for fish.)

  2. Meanwhile, make sauce: In a small bowl, whisk together mayonnaise, remaining 1/2 teaspoon tarragon, and lemon juice; season with salt and pepper. Set aside.

  3. Line a rimmed baking sheet with aluminum foil and brush with oil. In a food processor, place bread, a pinch each salt and pepper, and remaining tablespoon oil; pulse until fine crumbs form.

  4. Lay fillets flat on prepared baking sheet; season with salt and pepper. Spread top sides with mustard; sprinkle with bread crumbs, pressing to adhere. Bake on upper rack until fish is cooked through and crumbs are browned, 6 to 8 minutes. Serve with tomatoes and sauce.

Cook's Notes

If you don’t have dried tarragon on hand in the pantry, you can substitute dried oregano or dried basil.

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