1. Bring the vegetable stock to a good boil. Transfer the couscous to a ceramic dish or glass bowl. Then add the hot stock and stir.
2. Cover the dish for 10 minutes until the vegetable stock is fully absorbed.
3. Once the couscous is cooked and tender, stir it with a fork. Break up any lumps. Pour the olive oil in a pan and place it over medium heat until hot. Add the tomato paste.
4. Stir and fry the paste for 2 minutes. Then add the chopped onion.
5. Take the pan off the heat. Let the paste cool for 5 minutes. Then add the cooked couscous. Season with pepper and salt.
6. Stir well until the couscous is bright red. Add the chopped parsley and lemon juice.
7. Stir well. Check the seasoning. Add pepper, salt or lemon juice to taste. Transfer the tomato couscous to a bowl. Serve lukewarm or at room temperature.