Dinner

Roast Sea Bass & Vegetable Traybake Recipe

ByEthan Lark January 22, 2026January 22, 2026

Introduction

This roast sea bass and vegetable traybake is a simple, flavorful dish perfect for a healthy weeknight dinner. Combining tender sea bass with crispy red-skinned potatoes and vibrant peppers, it’s an easy recipe that requires minimal prep and cleanup.

A whole cooked fish with silver-grey skin lies flat in the center of a round white plate. On top of the fish, there are four thin slices of pale yellow lemon stacked slightly overlapping, and small green basil leaves placed around them. Surrounding the fish are roasted round slices of golden-brown potato and curved strips of red pepper, all resting on the white plate. Scattered among the potatoes and peppers are small black olives. A silver fork is placed on the left side of the plate, with a woman's hand reaching toward it. The plate sits on a white marbled textured surface. Photo taken with an iphone --ar 4:5 --v 7

Ingredients

300g red-skinned potatoes, thinly sliced into rounds
1 red pepper, cut into strips
2 tbsp extra virgin olive oil
1 rosemary sprig, leaves removed and very finely chopped
2 sea bass fillets
25g pitted black olives, halved
½ lemon, sliced thinly into rounds
handful basil leaves

Instructions

Step 1: Heat the oven to 180°C (160°C fan)/gas mark 4. Arrange the sliced potatoes and red pepper strips on a large non-stick baking tray. Drizzle with 1 tablespoon of the olive oil, then sprinkle with the chopped rosemary, a pinch of salt, and a good grind of black pepper. Toss everything together thoroughly to coat evenly.
Step 2: Roast the vegetables for 25 minutes, turning them over halfway through, until the potatoes are golden and crisp at the edges.
Step 3: Remove the tray from the oven and place the sea bass fillets on top of the vegetables. Scatter the halved olives over the fish, then place a few lemon slices on each fillet. Drizzle with the remaining tablespoon of olive oil.
Step 4: Return the tray to the oven and roast for a further 7–8 minutes, until the fish is cooked through and flakes easily with a fork.
Step 5: Serve the traybake scattered with fresh basil leaves for a fragrant finish.

Tips & Variations

For extra flavor, add a crushed garlic clove to the vegetables before roasting.
Try substituting thyme or oregano if you don’t have rosemary on hand.
Use other firm white fish fillets like cod or haddock if sea bass isn’t available.
Add cherry tomatoes for a burst of sweetness and color.

Storage

Store leftover traybake in an airtight container in the fridge for up to 2 days. Reheat gently in the oven or microwave until warmed through. For the best texture, reheat in the oven at 160°C to keep the potatoes crispy.

How to Serve

A white plate on a white marbled surface holds a cooked fish fillet placed in the center, its silvery skin shiny and slightly textured. Underneath and around the fish are thin, golden-brown roasted potato slices and a few roasted red pepper strips, adding warm tones. On top of the fish, three thin lemon slices form a neat stack, bright yellow with a juicy texture. Scattered around and on the fish are small black olives and fresh green basil leaves, adding pops of color and freshness. A silver fork rests on the left side of the plate with the tip touching the edge. A woman's hand holds the fork gently. Photo taken with an iphone --ar 4:5 --v 7

Serve this delicious recipe with your favorite sides.

FAQs

Can I prepare this dish ahead of time?

You can assemble the vegetables and seasonings a few hours before cooking and keep them covered in the fridge. However, it’s best to add the fish and roast just before serving for optimal freshness.

What if I don’t have a non-stick baking tray?

You can use a regular baking tray lined with parchment paper or lightly oiled to prevent sticking. Just be sure to check the fish doesn’t stick when turning or serving.