Cabbage tuna tajine

Ingredients :

For 6 people
 6 beautiful slices of tuna
 1 large green cabbage
 3 onions
 1 bunch of fresh coriander
 1/2 bouquet of flat parsley
 3 cloves of garlic
 0,2 grams of whole saffron
 1 teaspoon of cumin powder
 5 tablespoons of olive oil
 Salt and pepper.