- 10 minutes
- 20 minutes
- 4 to 6
- Rinse the mushrooms under water to clean.
- In a bowl, mix together the oil, vinegar, rosemary, salt, pepper, garlic, and thyme. Place the mixture in a zip-top bag with the mushrooms for several minutes.
- In a saucepan, melt the butter and sauté the onions until they're soft and brown.
- Transfer the mushrooms to the grill; cook 3 to 5 minutes per side or until they reach your desired level of doneness.
- Serve topped with sautéed onions.