Bring the water to a boil and boil the buckwheat bubbling for 1 min. Then reduce the heat and cook for about 15 minutes, until the water is absorbed, without stirring. Put in a large saucepan.
Heat the oil and sauté the peppers and onions. Add the zucchini and mushrooms and cook for 5 minutes, then transfer to the saucepan. Add the lentils, bay leaves, lemon juice, garlic, rosemary, cumin and vegetable stock and mix everything well. Bring everything to a boil and cook covered for about 30 minutes, until the lentils are good. Season with salt and pepper.
If you like, you can also top it with grated cheese.