1/2red onion, sliced into very thin rings, then halved
1teaspoonfresh herbs, finely chopped, see notes below
Mix all the dressing ingredients in a jar with secure lid. Shake well. Pour the dressing over the mushrooms and stir gently until everything is well coated. Store the salad in an airtight container in the refrigerator until you are ready to serve it.
For the fresh herbs, use your favorites. Parsley and chives work well together. Garlic chives work well too if you want to add a hint of garlic flavor. Fresh basil or oregano, mixed with parsley, work well for an Italian flavored mushroom salad. Tarragon is perfect for a more French flair.