- Wash and remove stems from mushroom caps.
- Chop the stems, and saute them, along with the onion in the margarine.
- Saute until the onion softens.
- Remove fromo heat.
- Let sit for about 5 minutes.
- Add remaining ingredients to onion mixture.
- Stuff the mushroom caps with the mixture.
- You may top with Parmesan cheese if desired.
- Place under broiler, watching closely, until stuffing bubbles.