Let this tangy mushroom-herb mixture cool to room temperature, then refrigerate for several days, or serve it right after it is thoroughly chilled.
Cut any large mushrooms in half. Heat oil in a large pan and add garlic. Do not brown. When oil is quite hot, add vinegar, coriander, bay leaf, thyme, and pepper. Cover and cook, shaking pan, for 1 minute. Add mushrooms and cover. Cook over high heat for 7 minutes, uncovering often to stir mushrooms. Remove from heat, cool slightly, and transfer mixture to a glass.