Remove mushroom stems; finely chop stems. Toss mushroom caps in lemon juice. In skillet, cook mushroom caps in butter 2 minutes per side. Remove caps to baking dish. Add remaining lemon juice, chopped mushrooms, onion and thyme to skillet. Cook until tender; remove from heat. Stir in spinach and cheese. Spoon into mushroom caps. Bake at 350F, 15 minutes or until heated through.
Microwave Directions: Remove mushroom stems; finely chop stems. Toss mushrooms caps in lemon juice. In microwavable bowl, combine onion, chopped mushrooms, thyme and 1 tablespoon butter; cook on high 3 minutes. Add spinach and cheese; mix well. Spoon into caps; arrange in 10-inch round pie plate. Cook on high 4 minutes, turning halfway through.
Cajun Country -- New Iberia, Louisiana