Set mushroom caps, gill side up, in a single layer in a lightly oiled 10- by 15- inch pan. Bake in a 400° oven until caps are flexible enough to bend easily, about 12 minutes (about 9 minutes in a convection oven).
* Percent Daily Values are based on a 2,000 calorie diet. Your daily value may be higher or lower depending on your calorie needs.