In a large skillet, heat olive oil over medium high heat. Add the onions and saute until it starts to brown, about 5 minutes. Add the mushrooms and saute for another 6-8 minutes until softened.
Add the soy sauce, garlic, thyme, and rosemary. Saute for 1 minute. Sprinkle flour all over the mushrooms and stir for 1 minute. Add the vegetable broth and stir until well combined. Simmer for 20 minutes (until thickened) stirring frequently. Taste and add salt and pepper to taste. Enjoy!
Note: If gluten-free, omit flour and add 2 Tbsp of cornstarch in small bowl with some liquid from the pan AFTER it has simmered for 20 minutes. Stir until it forms a smooth slurry. Add cornstarch mixture back into the pan and stir until gravy thickens.