Baked Trout in Foil with Lemon and Tomatoes

Jen was out at her book club and I couldn’t face a sink full of pans, so the whole trout went into a foil parcel with cherry tomatoes, red onion, garlic and lemon. Everything steams together in one packet. The fish comes out moist and flaky, the tomatoes collapse into a rough sweet sauce, and the garlic turns soft and mellow. She requests it now, which is saying something.

Why this baked trout in foil works

Foil packets are brilliant. They trap the steam and the flavour, so the fish cooks gently and stays juicy rather than drying out the way it does under a hot grill. The tomatoes collapse and mix with the olive oil and lemon juice to make a rough sauce you spoon over everything, and because you’re not standing over a pan, you can get on with something else while it bakes. It’s very easy and very tasty.

I use a whole trout because it looks impressive and the bones help keep the flesh moist, though if you’d rather not deal with bones, fillets work just as well. The principle stays the same: season, wrap, bake. The NHS advises two portions of fish a week, one of which should be oily, so really this is me being responsible. Jen remains unconvinced.

Ingredient notes and substitutions

Trout is the star, but salmon works if you prefer it. Salmon fillets are thicker, so they may want a little longer. Sea bass or bream would also be lovely. Ask your fishmonger to clean and gut the trout for you. If you’re using fillets, get the ones with skin on, as they hold together better.

Cherry tomatoes are ideal because they’re sweet and burst nicely. If you only have larger tomatoes, chop them into chunks. Red onion adds a bit of sharpness, but a yellow onion or even a shallot will do. Garlic cloves, leave them whole and just crush them with the flat of your knife. They go sweet and soft in the oven. Don’t bother chopping them finely, as they’ll just burn.

Lemon is essential. I slice half of it and tuck those slices inside the fish, then squeeze the juice from the other half over the vegetables. If you’ve got fresh thyme or rosemary, chuck a few sprigs in. Dried herbs are fine too, and I use a mix of thyme and rosemary. Olive oil, salt and pepper. That’s it. No need for anything fancy.

Step-by-step

First, get your oven on to heat up. While it’s warming, pat the trout dry with kitchen paper, which helps the oil and seasoning stick. Rub it all over, inside and out, with olive oil, then sprinkle with salt, pepper and dried herbs. If you’re using a whole fish, tuck a few lemon slices and a crushed garlic clove inside the cavity. This flavours the flesh from the inside.

Next, tear off a big sheet of foil and put it on a baking tray. Scatter the cherry tomatoes, sliced onion and remaining garlic over the foil. Drizzle with the rest of the olive oil and squeeze over the lemon juice. Toss everything together with your hands so it’s all coated. Then sit the trout on top. If you have any lemon slices left over, lay them over the fish.

Now fold the foil up and over the fish to make a loose packet. Don’t wrap it too tight, as you want a bit of room for the steam to circulate. Seal the edges well so no steam escapes. Put the tray in the oven and bake until the fish is cooked through. You’ll know it’s done when it flakes at the thickest part and reaches 145°F (63°C) on a thermometer. Or do what I do and have a poke about with a fork.

Carefully open the foil, watching out for hot steam, because it will billow out. The tomatoes should be blistered and soft, the onions translucent, and the fish moist. Garnish with fresh herbs if you have them. Serve straight away with the cooking juices spooned over.

Tips

• Don’t overcook the fish. Check it a few minutes before you think it’s ready, as trout dries out quickly if left too long.
• If you’re using fillets, reduce the baking time, as they cook faster than a whole fish.
• Let everyone help themselves from the foil. Put the whole tray in the middle of the table and let them get on with it.
• If you want extra lemon for squeezing at the table, slice up a second one and keep it on the side.

As a tip, if you don’t have foil, you can use baking parchment, but it won’t seal as tightly. The steam will escape and the fish might dry out a bit. Foil is best.

Make-ahead, freezing and reheating

You can prep the vegetables and lemon up to a day ahead. Slice the onion, crush the garlic, and keep them in a covered bowl in the fridge. Assemble the packet just before baking. If you want to freeze, cook the dish first, then cool it completely. Wrap the whole packet or portions tightly in foil and freeze for up to a month. To reheat, thaw overnight in the fridge, then warm in a covered oven dish at a low temperature until just heated through. You can reheat from frozen, but it will take longer, so add about fifteen minutes and check it’s piping hot. Be careful not to overcook, or the fish will dry out. I’d rather eat this fresh, but leftovers are still good.

Troubleshooting

If you overcook it, there’s no going back. A squeeze of lemon and a drizzle of oil hides a multitude of sins, though. If the fish is underdone, just seal the foil back up and return it to the oven for a few more minutes. If the tomatoes haven’t burst, they might need a bit more time, but they’ll still taste sweet. If the foil leaks, put the whole thing on a rimmed baking tray to catch the juices. And if you’re worried about bones, use fillets instead.

Variations and what to serve with it

You can add other vegetables to the packet, such as sliced courgette, fennel, or even new potatoes, though par-boil them first. A splash of white wine instead of lemon juice is nice. For a bit of heat, add a pinch of chilli flakes. Serve with crusty bread to mop up the juices, or with rice, couscous, or simply a green salad. Jen likes it with buttered new potatoes. I like it with a glass of something cold.

More fish dinners worth trying include steamed salmon, parmesan and paprika haddock with garlic butter, and our round-up of recipes for cooking fish.

Baked trout in foil – the verdict

This is one of those dishes that delivers far more than the effort suggests. Healthy, too, which after the rest of this week’s eating is probably for the best. Though I did have mine with a glass of something cold, so let’s not get carried away. Jen’s already asked for it again Friday. I may have created a monster, but at least there’s no washing up. As always, many thanks for reading and until next time…Steve.

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Steve Deacon

Founder & Writer

Hi, I'm Steve, founder of The Yum Yum Club. After years in the corporate rat race traveling the world, my wife Jen and I settled back in the UK to follow our true passion: great food and wine. Having worked in restaurant kitchens in my youth, I share honest home-cooked recipes, kitchen timing tips, and culinary discoveries.

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