Eat sustainable seafood

1. Place the onion, carrots, tomatoes and parsley in a large saucepan or casserole dish, then layer the lemon slices on top. Add the bay leaves and pour in enough cold water to just cover the contents. Bring to the boil, then reduce to a medium heat and simmer for 10 minutes.

2. Lay your fish on top of the ingredients, leaving the fillets whole. If your prawns are raw, also add them in at this stage. If they are ready cooked, don't add them yet. Season with a generous amount of sea salt and pepper, and sprinkle over the sumac if using. Pour in the olive oil - the liquid level should only just be covering the fish (gently push the fish down into the liquid if needed). Add a little more water if the liquid level is too low.

3. Bring the pot back to the boil, then lower the heat and cover, before gently simmering for around 10 minutes- or until the fish is tender. If your prawns are ready cooked, add them to the pot in the last two minutes to ensure they're warmed through.

4. Ladle some fish, vegetables and liquid into bowls. Sprinkle with a little more chopped parsley, serve with lemon wedges (to be squeezed over to taste), and slices of crusty bread to mop up all the juices.

Tip: to get the skin off a tomato easily, lightly score the whole way around the fruit twice, so the scores cross. Submerge the tomatoes in a bowl of boiling water for a minute or so. Then remove and the skin will easily peel away.

Tip: to get your lemon really thinly sliced, use a mandolin. Or get them as thin as you can with a very sharp knife. Remove any pips you see in the slices.