1) In a 9-inch nonstick skillet, heat oil.
2) To the hot oil, add onions.
3) Over high heat, cook the onions for a minute, stirring in between.
4) Now turn the heat to medium-high.
5) To the skillet, add the mushrooms and saute for 4 minutes.
6) Gradually add the chicken broth and mix gently.
7) Cook this mixture for 2 minutes, or until thick. Stir as required.
8) Now, add the remaining ingredients and mix well.
9) Cook for a minute, or until the vinegar has evaporated well.
10) Serve the Mushroom and Onion Saute along with a bowl of noodles or hot cooked rice.