Heat the oil in a saucepan. Add the onions and garlic with a pinch of salt and some ground black pepper and saute until the onions start to soften, about 3-4 minutes.
Add the white wine to the pot, if using, and saute until there is no visible liquid left, about 3-4 minutes.
Add the rice flour and stir for a couple of minutes. If the flour begins to stick to the bottom, scrape it up with the ladle.
Add the tomato paste, stir it in, and then add tomatoes. Let the tomatoes cook down for another 2-3 minutes.
Add the herbs, mix well, then add the mushrooms. Saute for a couple of minutes until the mushrooms begin to express their juices, then add the tamari or soy sauce or liquid aminos, vegetable stock, and season as needed with ground black pepper and salt.
Let the mixture come to a boil and continue to cook for a couple of minutes. If it looks too dry, add more stock, a little at a time. I like this stew rather thick, but you can think it out according to your taste.
Garnish with parsley and serve hot over pasta, rice, or with crusty bread.