In a medium saucepan, bring 1 cup vegetable stock to a boil. Stir in the quinoa and reduce heat to low. Cover and simmer for 20 minutes.
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.
Stir the vegetable-tofu mixture into the cooked quinoa. Cover, and allow to sit for 10 minutes before serving.