Ingredients:

• 1 pound ripe but firm small round or plum tomatoes, cut into 1/2-inch-thick wedges

• 2 medium yellow onions, cut into 1/4-inch-thick wedges

• 1 tablespoon finely slivered orange zest (see Tips)

• 1 tablespoon extra-virgin olive oil

• 1 tablespoon chopped fresh thyme leaves, plus sprigs for garnish

• 1/2 teaspoon kosher salt, divided

• Freshly ground pepper, to taste

• 1 pound boneless, skinless cod (see Tips) or other thick-cut, firm-fleshed fish, cut into 4 equal portions

Preparation:

• Preheat oven to 400°F.

• Combine tomatoes, onions, orange zest, oil and chopped thyme in a 3-quart glass or ceramic baking dish. Sprinkle with 1/4 teaspoon salt and pepper; stir to combine.

• Roast, stirring occasionally, until the onions are golden and brown on the edges, about 45 minutes. Remove from the oven. Increase oven temperature to 450°F.

• Push the vegetables aside, add fish and season with the remaining 1/4 teaspoon salt and pepper; spoon the vegetables over the fish.

• Return the baking dish to the oven and bake until the fish is opaque in the center, about 10 to 12 minutes. To serve, divide the fish and vegetables among 4 plates and garnish with thyme sprigs.