Preheat the oven to 180C/350F/Gas 4.
For the couscous, pour the couscous into a large saucepan and add the saffron, stock and olive oil. Heat gently for about 5-6 minutes and then remove from the heat.
Combine the lemon juice and zest and the chopped herbs in a bowl and add to the couscous. Finally fold in the chopped tomato.
For the roasted tomatoes, heat the oil in an ovenproof frying pan and fry the tomatoes, turning once, until they have taken on some colour. Season with salt and freshly ground black pepper and add the thyme sprigs and garlic to the pan. Place the pan into the oven to roast the tomatoes for 10-12 minutes.
To serve, pile the couscous onto a serving plate and top with the roasted tomatoes.