Preheat oven to 450F. Place mushrooms in a large 9x13' pan or big enough to fit them all in one layer. Toss with olive oil and garlic. Turn the mushrooms stem side up. Season with salt and pepper and the thyme. Dot the tops with butter.
Bake for 18-20 min. or until golden and bubbly. Serve hot with steak or alone with bread for dipping.
Nutrition calculation is an estimation only. If you need nutritional calculations for medical reasons, please use a source that you trust.