While quinoa is cooking, heat olive oil in a skillet over medium heat. Add the garlic, broccoli florets, and tofu. Stir for a minute, then cover and steam over low heat for 2 minutes. Stir in 1/4 cup vegetable broth, mushrooms, and spinach. Cover and cook over medium heat until the mushrooms are soft and spinach is wilted, about 3 minutes.