In a food processor combine the tahina, lemon juice, salt, chilli, dried and fresh coriander, whole walnuts. The colour should be a lighter colour to the tahina due to the addition of the lemon juice. The consistency should be slightly runny. Add water to ensure that this happens.
Marinate the fillets in a bowl with this sauce at least for 4 hours.
The fish can be wrapped in foil and cooked in a pre-heated oven on 180C for about 50 minutes. I place the fillets in an open baking tray and cook for about 40 minutes in a pre-heated oven set at 200 degrees. I test if it is ready by pressing against the fish and allowing an egg flip to fall easily through the fillet.
Serve with lemon wedges, a sprinkle of the chopped walnuts and parsley on top.