Heat the oil or water in a large saucepan over medium heat. Add the onion and cook until soft, about 7 minutes. Add the garlic and mushrooms and cook about 3 minutes or until the mushrooms are tender.
Stir in the rice and cook, stirring, for 1 to 2 minutes. Stir in the vegetable broth and bring to a boil. Reduce the heat, season with salt and pepper to taste, cover, and simmer for 35 minutes, stirring occasionally.
Uncover, and add the scallions and spinach, stirring until the spinach wilts. Stir in the beans and dill. Cook for 5 minutes longer, or until the broth is absorbed and the rice is tender. Taste and adjust the seasonings if needed. Serve hot.