Method:
In a large skillet over medium-high heat, bring 1/2 cup broth to a simmer. Add onion and garlic and cook for about 4 minutes or until onion is translucent. Stir in mushrooms, rosemary and thyme and continue to cook about 2 minutes or until mushrooms release their liquid and start to become tender. Add wine and cook 1 minute, stirring constantly. Stir in remaining 3 cups broth and bring to a simmer.
Meanwhile, in a small bowl, whisk together tamari, yeast and flour to form a thick paste. Add mixture to skillet about 1 teaspoon at a time, whisking constantly to make sure paste dissolves. Bring to a boil and boil 1 minute, stirring constantly. Add pepper.