Heat oven to 375°F. Spray 13x9-inch (3-quart) glass baking dish with cooking spray. In 12-inch skillet, heat 1 tablespoon of the oil over medium-high heat. Add half of the mushrooms; cook, stirring occasionally, 4 to 6 minutes or until tender. Spoon into medium bowl. Repeat with 1 tablespoon oil and remaining mushrooms. Add 1/2 teaspoon salt to mushrooms; toss to coat.