Clean and wash the peppers, zucchini, navettes and aubergines. Cut peppers into pieces or rhombs, courgettes into slices and turnips into slices. Dice aubergine. Drain tomatoes on a sieve, chop.
Bring the stock to the boil, cook the turnips for about 10 minutes. Peel and chop the onion. Peel garlic, crush finely. Heat olive oil in a wide saucepan. Brown the aubergine cubes in it. Add bell pepper, zucchini, onion and garlic and braise.
Add tomato juice, navettes and stock. Season with salt, cayenne pepper, 1/2 jar of saffron, cinnamon, allspice, cumin and cardamom. Simmer covered for 5-10 minutes. During the last 2 minutes add tomato pieces.
Season again, keep warm. Bring 1/4 litre of salted water to the boil, remove from heat, stir in oil and couscous. Leave to swell for 3-5 minutes until all liquid has been absorbed. Place back on the stove and stir several times with a fork to make the couscous loose and granular.
Arrange on a plate with the vegetables.