Heat oil in a non-stick pan, add garlic and sauté for half a minute. Add thyme and mushrooms and sauté on high heat for four to five minutes. Add whole wheat flour and sauté for two to three minutes more.
Add four cups of vegetable stock, salt and mix well. Let the mixture come to a boil, reduce heat and simmer till mushrooms are cooked. Take the pan off the heat and allow to cool.
Transfer half the mixture into a blender jar and grind coarsely.
Transfer the ground mixture back into the pan. Add the remaining vegetable stock if the consistency is too thick and mix well. Boil for three to four minutes. Serve hot.