In a medium saucepan, bring vegetable broth to a simmer over medium heat.
Meanwhile, in a medium frying pan, heat 1 Tablespoon olive oil over medium heat. Sautee onions and garlic until lightly browned, stirring to keep from burning.
Once vegetable broth is simmering and onions are lightly browned, pour both into a medium-large pot with a lid. Pour in the rice and stir to combine.
Bake for 45 minutes, covered.
After it has baked for 45 minutes, in a medium frying pan, heat 1 Tablespoon olive oil over medium heat. Sautee mushrooms, spinach and salt until spinach cooks down completely. Pour into baked rice. Bake for another 10-20 minutes, or until rice has fully absorbed the rice.
Remove from oven and sprinkle feta on top. Serve hot.
Notes
*The baking time may vary depending on how wide the pot you're using is.