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

　　

Ingredients

serves 4

　　6 plum tomatoes, halved lengthwise

　　2 tablespoons olive oil, plus more for baking sheet

　　3/4 teaspoon dried tarragon or dried oregano

　　Pinch of sugar

　　Coarse salt and freshly ground pepper

　　1/3 cup mayonnaise

　　1 tablespoon fresh lemon juice

　　3 slices white sandwich bread, torn into large pieces

　　4 flounder fillets (1 1/2 pounds)

　　2 tablespoons Dijon mustard

　　

Step 1

Preheat oven to 450°F, with racks in upper and lower thirds. Place tomatoes on a rimmed baking sheet. Drizzle with 1 tablespoon oil, and sprinkle with 1/4 teaspoon tarragon and the sugar; season with salt and pepper. Toss to coat. Arrange tomatoes in a single layer, cut sides up. Roast on lower rack until tender, 20 to 25 minutes.

　　

Step 2

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

　　

Step 3

Lightly oil another rimmed baking sheet. In a food processor, pulse bread with a pinch each of salt and pepper and remaining tablespoon oil until fine crumbs form.

　　

Step 4

Pat fish dry with paper towels, and season both sides with salt and pepper. Place fillets on prepared baking sheet. Dividing evenly, spread mustard on top; sprinkle with bread crumbs, gently pressing to adhere. Bake on upper rack until fish is cooked through and coating is browned, 6 to 8 minutes. Serve with roasted tomatoes and sauce alongside.

　　Everyday Food: Fresh Flavor Fast by Martha Stewart Living Magazine. Copyright © 2010 by Martha Stewart Living Magazine. Published by the Crown Publishing Group. All Rights Reserved.Martha Stewart Living magazine was first published in 1990. Over the years, more than two dozen books have been published by the magazine’s editors.Martha Stewart is the author of dozens of best-selling books on cooking, entertaining, gardening, weddings, and decorating. She is the host of The Martha Stewart Show, the successful daily syndicated television show.