Combine first 4 ingredients in a small bowl. Place mushrooms and flour in a plastic bag; seal and shake gently to coat.
Heat oil in a large nonstick skillet on medium heat. Dip mushrooms in egg mixture. Place mushrooms cap-side down in skillet; saute 2 minutes per side or until golden brown. Sprinkle lemon juice evenly over mushrooms. Remove mushrooms from skillet, and place on a baking sheet. Bake at 400° for 10 minutes or until mushrooms are tender.