In a medium pot, heat the butter and olive oil over medium heat. Add the onions and garlic and cook about 3 minutes or until tender
Add the rice, stir with a wooden spoon to coat well, and cook for 1 minute.
Add the spinach, broth and salt, bring to a boil, stir and decrease the heat to low.
Cover and cook for about 20 minutes or until the water is absorbed and the rice is tender.
Remove from the heat and let rest for 5 minutes.