Mediterranean seafood gratin

Mediterranean seafood gratin
  • High protein
  • Low fat
  • Low phosphate
  • Low potassium
  • Low salt
  • Main meal
  • European
  • 90 minutes or less
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This tasty seafood recipe is nice and light, as well as low in potassium and phosphate. It’s great to share, or can be cooked and frozen for another day.


1 tablespoon olive oil

1 small onion

1 garlic clove

1 teaspoon fennel seeds

1 teaspoon coriander seeds

100ml white wine (optional) or water

400g tin of chopped tomatoes with herbs

1 tablespoon tomato puree

1 pinch saffron (optional)

1 bay leaf

½ tablespoon lemon juice

½ tablespoon flat leaf parsley

300g skinless, boneless unsmoked fish

150g raw peeled prawns

Gratin topping

30g Parmesan cheese

50g dried breadcrumbs

Black pepper

½ tablespoon flat leaf parsley

Side salad

75g green salad

½ yellow pepper (approx. 75g)

4 x 60-70g crusty rolls


  1. Step 1

    Preheat the oven to 200C/gas mark 5. Peel and thinly slice the garlic and onion. Heat the oil, adding the onions, garlic, and fennel seeds. Lightly crush the coriander seeds using the bottom of a heavy pot before adding to the pan.

  2. Step 2

    Stir regularly for 15 minutes. Take off the heat and pour in the wine/water. Return to the heat, cook for 2 mins and then add the tomatoes, tomato puree, saffron, bay leaf and season with black pepper. Lower the heat and gently simmer for 15 minutes, stirring occasionally.

  3. Step 3

    Roughly chop the parsley, stir it in and add the lemon juice. Cut the fish into even sized chunks and add to the dish, along with the prawns. Stir and bring to the boil for 4-5 minutes. If freezing, cook for an extra 2-3 minutes.

  4. Step 4

    Transfer the mixture into a large ovenproof dish or, if making individual portions, divide evenly between four small dishes. Place on a baking tray.

  5. Step 5

    Grate the Parmesan and mix it with the breadcrumbs, parsley, and black pepper. Sprinkle it over the top and bake in the oven for 20 minutes until golden brown.

  6. Step 6

    Wash and prepare a salad of lettuce leaves, sliced cucumber and diced pepper. Serve the seafood gratin with the salad and a crusty roll to mop up the sauce.

Food facts

The breadcrumbs and crusty roll are the main sources of carbohydrate in this dish. The carbohydrate value of the crusty roll is estimated to be 43.5g; if you choose not to have the roll, adjust your insulin accordingly.

Whilst tomatoes are a high potassium food and prawns are a high phosphate food, the quantities used in this recipe mean that it is a low potassium and low phosphate dish overall. If you have been prescribed a phosphate binder, ensure you take them with this dish.

The fish and prawns make this a high protein meal, which makes it suitable for those receiving dialysis.

Use gluten-free breadcrumbs and a gluten-free crusty roll.

Avoid smoked fish for this dish, as smoked fish is higher in salt.

Choose a cheaper white fish or look for frozen fish fillets. Wine can be purchased in mini bottles or it can be replaced with the same quantity of water. If the saffron is out of your budget, simply leave it out.

This dish is best eaten fresh, the same day it is cooked. If freezing, then once the topping has been added, don’t bake and allow to cool. Cover with a double layer of foil, and freeze for up to one month. To serve, defrost overnight in the fridge then bake for 25 mins or until piping hot throughout.

If you have had a transplant, you should buy your fish pre-packaged, rather than from a fresh fish counter, in order to avoid risk of bacterial contamination.