1. Boil spinach for one minute, drain and reserve the liquid. 2. Put 450 ml of the water into a pan and add the Lentils. 3. Cover and cook over a medium-low heat for 20 minutes. 4. Meanwhile, heat 1 tbs of oil in a large frying pan and cook the Onion and garlic for about 10 minutes until soft and golden. 5. Stir the Mushrooms into the onions, increase the heat and season generously. 6. Cook until juicy and darkened in colour. 7. Add the tomatoes to the pan and cook briskly for 5 minutes until thickened but still quite liquid. 9. Simmer gently for a few minutes.