Over medium heat, add baby spinach, water, and soy sauce to a skillet and cook until the spinach is wilted and reduced. Set aside the spinach in a bowl.
Add your sliced shiitake mushrooms, soy sauce, and granulated garlic to the same skillet. Over medium heat, sauté the mushrooms until tender but still firm.
Assemble the bowls by adding rice to the bottom of each bowl for each person. Pour vegan egg yolk sauce into the center of each bowl. Distribute the bibimbap vegetables and tofu among the four bowls.