Baking and Roasting Fish
Cooking Skills: Fish and Shellfish 1
Chapter 3 · Baking and Roasting Fish
Skill goal
Bake fish in the oven so it stays moist, with a tray, a parcel or a crumb crust.
Shopping list for this chapter
The basics
Baking is the easiest way to cook fish for a crowd or while you do something else. Dry oven heat can also dry fish out quickly, so every method here protects the fish in some way: a foil parcel traps steam and cooks the fish in its own juices; a crumb topping shields the top and adds crunch; and a bed of vegetables keeps the underside moist. A fillet about 2.5 cm thick is done in 12 to 15 minutes at 200°C; thin fillets are done in under 10.
Fish keeps cooking as it rests, so take it out when the thickest part has just turned opaque. A lower oven (120°C) cooks gently and gives a very tender, forgiving result, though without browning. Vegetables that take longer than the fish, such as potatoes, need a head start; see Cooking Skills: Potatoes 1, chapter 3 for roasting them. Fish pie, which is also baked, is in chapter 5.
The method
- Heat the oven fully before the fish goes in; a preheated tray also helps the underside cook.
- Pat the fish dry, season it and brush or drizzle with oil or butter so it does not dry.
- Give slow vegetables a head start so everything is ready together.
- Check at the minimum time: the thickest part should flake and have no glassy centre.
- Rest for 2 minutes before serving; it keeps cooking and the juices settle.
| Method | Oven (approximate) | Time | Result |
|---|---|---|---|
| Open tray | 200°C (180°C fan, gas 6) | 12 to 15 minutes | Lightly browned, firm |
| Foil parcel | 200°C (180°C fan, gas 6) | 15 to 20 minutes | Soft, steamed, flavoured |
| Crumb top | 200°C (180°C fan, gas 6) | 15 minutes | Crisp top, moist inside |
| Low and slow | 120°C (100°C fan, gas ½) | 20 to 25 minutes | Very tender, silky |
Hot oven, hot steam from parcels and raw fish
Hot oven and hot trays: ovens, trays and tins are hot enough to burn badly. Use dry oven gloves (a damp cloth conducts heat), pull the shelf out a little before lifting a tray, put hot things on a heatproof surface and keep children away from the oven door.Steam from a parcel: a foil parcel holds scalding steam. Open it away from your face, slitting the top with a knife and letting the steam escape before you peel it back.
Raw fish: keep raw fish on its own board and plate, away from food that won't be cooked. Wash your hands, boards and knives in hot soapy water afterwards, and store raw fish on a plate on the bottom shelf of the fridge so it can't drip onto other food.
Is it cooked?: fish is done when the flesh turns opaque (no longer glassy) and flakes easily with a fork. A probe thermometer reads about 63°C in the thickest part (general guidance). Take it off the heat a minute early, because it keeps cooking as it rests.
Try it
Level 1 · Start here
A salmon traybake
The classic one-tray supper. Potatoes need 25 minutes, broccoli 10 and salmon 12 to 15, so they go in at different times. Lemon and olive oil are all the seasoning it needs.
Ingredients (2 portions)
- 300 g baby new potatoes, halved
- 2 tbsp olive oil
- 2 salmon fillets (about 150 g each), skin on
- 150 g broccoli, in florets
- 1 lemon, half sliced, half cut in wedges
- ½ tsp flaked sea salt
- Heat the oven to 200°C (180°C fan, gas 6). Toss the potatoes with half the oil and the salt on a large tray and roast for 15 minutes.
- Add the broccoli and the salmon (skin side down) to the tray, drizzle with the rest of the oil and lay the lemon slices on top. Roast for 12 to 15 minutes more.
- The salmon is done when it flakes in the thickest part. Rest for 2 minutes and serve with lemon wedges.
Hot oven, hot tray and allergens
Hot oven and hot trays: ovens, trays and tins are hot enough to burn badly. Use dry oven gloves (a damp cloth conducts heat), pull the shelf out a little before lifting a tray, put hot things on a heatproof surface and keep children away from the oven door.Raw fish: keep raw fish on its own board and plate, away from food that won't be cooked. Wash your hands, boards and knives in hot soapy water afterwards, and store raw fish on a plate on the bottom shelf of the fridge so it can't drip onto other food.
Is it cooked?: fish is done when the flesh turns opaque (no longer glassy) and flakes easily with a fork. A probe thermometer reads about 63°C in the thickest part (general guidance). Take it off the heat a minute early, because it keeps cooking as it rests.
Allergens: fish is one of the 14 major allergens, and cross-contact is easy: it can pass on boards, oil, tongs and pans. Crustaceans (prawns), molluscs (mussels, scallops), gluten, milk and egg also appear in fish recipes. Always tell guests what is in a dish.
Level 2 · Parcel
Cod in a foil parcel
Fish, vegetables and flavourings wrapped in foil steam in their own juices, and the parcel makes its own sauce. Make sure the foil is sealed all round or the steam escapes. Open it carefully at the table.
Ingredients (2 portions)
- 2 cod fillets (about 150 g each)
- 150 g cherry tomatoes, halved
- 1 courgette, in thin ribbons
- 2 tbsp olive oil
- 1 lemon, 4 slices
- 4 sprigs of thyme
- ½ tsp flaked sea salt
- Heat the oven to 200°C (180°C fan, gas 6). Tear 2 large sheets of foil and brush the centre with oil. Pile courgette and tomatoes in the middle of each.
- Lay a fillet on each, season, top with lemon slices and thyme, drizzle with oil, and fold the foil over to make a sealed parcel.
- Bake on a tray for 15 to 18 minutes. Open carefully (steam!), check the fish flakes, and serve with the juices.
Hot parcel, steam and allergens
Hot oven and hot trays: ovens, trays and tins are hot enough to burn badly. Use dry oven gloves (a damp cloth conducts heat), pull the shelf out a little before lifting a tray, put hot things on a heatproof surface and keep children away from the oven door.Raw fish: keep raw fish on its own board and plate, away from food that won't be cooked. Wash your hands, boards and knives in hot soapy water afterwards, and store raw fish on a plate on the bottom shelf of the fridge so it can't drip onto other food.
Is it cooked?: fish is done when the flesh turns opaque (no longer glassy) and flakes easily with a fork. A probe thermometer reads about 63°C in the thickest part (general guidance). Take it off the heat a minute early, because it keeps cooking as it rests.
Allergens: fish is one of the 14 major allergens, and cross-contact is easy: it can pass on boards, oil, tongs and pans. Crustaceans (prawns), molluscs (mussels, scallops), gluten, milk and egg also appear in fish recipes. Always tell guests what is in a dish.
Level 2 · Crisp
Crumb-topped haddock
A layer of mustard glues on a herby crumb that bakes into a crisp lid, protecting the fish underneath. Use fresh breadcrumbs for the best crunch, and drizzle with oil so they brown.
Ingredients (2 portions)
- 2 haddock fillets (about 150 g each), skinned
- 2 tsp Dijon mustard
- 50 g fresh breadcrumbs
- 2 tbsp chopped parsley
- 1 lemon, zest and wedges
- 2 tbsp olive oil
- 1 pinch flaked sea salt
- Heat the oven to 200°C (180°C fan, gas 6). Mix the breadcrumbs, parsley, lemon zest, salt and 1 tbsp of the oil.
- Place the fillets on an oiled tray, brush the tops with mustard and press the crumbs on firmly.
- Drizzle with the remaining oil and bake for 12 to 15 minutes until the crumbs are golden and the fish flakes. Serve with lemon wedges.
Hot oven and allergens
Hot oven and hot trays: ovens, trays and tins are hot enough to burn badly. Use dry oven gloves (a damp cloth conducts heat), pull the shelf out a little before lifting a tray, put hot things on a heatproof surface and keep children away from the oven door.Raw fish: keep raw fish on its own board and plate, away from food that won't be cooked. Wash your hands, boards and knives in hot soapy water afterwards, and store raw fish on a plate on the bottom shelf of the fridge so it can't drip onto other food.
Is it cooked?: fish is done when the flesh turns opaque (no longer glassy) and flakes easily with a fork. A probe thermometer reads about 63°C in the thickest part (general guidance). Take it off the heat a minute early, because it keeps cooking as it rests.
Allergens: contains fish, gluten and mustard.
Level 3 · Roast
Mackerel with roast potatoes and tomatoes
Mackerel is oily and strong, and goes well with sweet roasted tomatoes and crisp potatoes. The fish goes in last, because it cooks in 10 to 12 minutes. The oils run into the potatoes below.
Ingredients (2 portions)
- 400 g waxy potatoes, in 2 cm chunks
- 2 tbsp olive oil
- 200 g cherry tomatoes
- 2 mackerel fillets, skin on
- 1 tbsp chopped parsley
- 1 lemon, in wedges
- ½ tsp flaked sea salt
- Heat the oven to 220°C (200°C fan, gas 7). Toss the potatoes with the oil and salt on a large tray and roast for 30 minutes until golden.
- Add the tomatoes and lay the mackerel fillets on top, skin side up. Roast for 10 to 12 minutes more until the skin is blistered and the fish flakes.
- Scatter with parsley, and serve with lemon wedges.
Hot oven, bones and allergens
Hot oven and hot trays: ovens, trays and tins are hot enough to burn badly. Use dry oven gloves (a damp cloth conducts heat), pull the shelf out a little before lifting a tray, put hot things on a heatproof surface and keep children away from the oven door.Bones: even fillets can hide thin pin bones. Run a clean finger along the fillet and pull any bones out with tweezers, and warn children and anyone you serve. Whole sardines and mackerel have fine bones that are best taken out.
Smoked and oily fish for some people: pregnant women, young children, the elderly and people with weak immune systems are advised to limit oily fish and shark, swordfish and marlin, and to avoid raw or lightly cooked shellfish and, for some, cold-smoked fish. This is general guidance, not medical advice: check current health guidance if it applies to you.
Is it cooked?: fish is done when the flesh turns opaque (no longer glassy) and flakes easily with a fork. A probe thermometer reads about 63°C in the thickest part (general guidance). Take it off the heat a minute early, because it keeps cooking as it rests.
Experiments
Experiment
Parcel or open tray
Texture.
- Bake two cod fillets, one in a sealed foil parcel and one on an open tray, for the same time.
Look for: The parcel is soft and steamed with a lot of juice; the open fillet is firmer and slightly browned. Choose by what you want.
Experiment
High oven or low
Tenderness.
- Bake two pieces of salmon, one at 200°C for 12 minutes and one at 120°C for 22 minutes.
Look for: The low oven gives silky, even flesh with no browning; the high one is firmer and browned at the edges.
Experiment
Resting
Juices.
- Cut one fillet straight from the oven and rest another for 2 minutes.
Look for: The rested one finishes cooking and holds its juice; the other loses moisture and looks glassy at the centre.
Experiment
Thick or thin fillet
Timing.
- Bake a thin and a thick piece of the same fish together and check them every 2 minutes.
Look for: The thin piece is done long before the thick. Always cook equal thicknesses together.
Tasting notes
| What I tried | Method or amount | What I saw | What I thought | Will I do it again? |
|---|---|---|---|---|
| Salmon traybake | ||||
| Cod in a foil parcel | ||||
| Crumb-topped haddock | ||||
| Mackerel with potatoes | ||||
| Parcel or open tray | ||||
| High oven or low | ||||
| Resting | ||||
| Thick or thin fillet |
Troubleshooting
| Problem | Likely cause | What to do |
|---|---|---|
| Dry fish | Overbaked or oven too hot | Check early; use a parcel or lower oven |
| Soggy crumb | Crumbs not oiled or fish wet | Pat the fish dry; toss crumbs in oil; bake hot |
| Raw in the middle | Fish too thick or cold from the fridge | Bake longer; let the fish stand for 10 minutes first |
| Potatoes undercooked | Not given a head start | Roast them for 15 to 30 minutes before adding fish |
| Parcel leaks | Foil not sealed | Fold the edges twice and press |
| Fish sticks to the tray | Tray not oiled | Line with parchment or oil it |
Hot oven, hot steam and leftovers
Hot oven and hot trays: ovens, trays and tins are hot enough to burn badly. Use dry oven gloves (a damp cloth conducts heat), pull the shelf out a little before lifting a tray, put hot things on a heatproof surface and keep children away from the oven door.Is it cooked?: fish is done when the flesh turns opaque (no longer glassy) and flakes easily with a fork. A probe thermometer reads about 63°C in the thickest part (general guidance). Take it off the heat a minute early, because it keeps cooking as it rests.
Leftover fish: cool cooked fish quickly, refrigerate it within 1 to 2 hours, and eat it within about 1 day (2 at most). Reheat only once, until steaming hot all the way through. Do not refreeze fish that was frozen and thawed unless you cook it first.
Checkpoint: can you do this now?
- I can time vegetables and fish on one tray.
- I can seal and open a foil parcel safely.
- I can make a crisp crumb topping.
- I can tell when baked fish is done.
- I know to rest fish before serving.
Next chapter
Cooking Skills: Fish and Shellfish 1, chapter 4 is Poaching and Steaming: cooking fish gently in liquid.