Heat the olive oil in a large skillet over medium heat.
Add the shallot and cook until soft, about 4 minutes.
Add the mushrooms and cook until soft, about 8 to 10 minutes.
Stir in the tamari, garlic, thyme, and rosemary.
Sprinkle the flour over the mushrooms and stir for 1 minute.
Add the broth and simmer until thickened, whisking often, about 20 minutes.
Season with salt and pepper to taste.
