Dry meat with paper towels. Combine salt, pepper and flour; dredge medallions in flour, shaking off excess. Beat eggs with water; dip medallions in egg and coat with bread crumbs. Press medallions with heel of palm to make crumb stick; dry 10 minutes.
Heat butter and oil in Dutch oven; saute medallions 8 minutes per side. Remove meat; drain on paper towels, transfer to heated platter and keep warm. Add wine to pan; deglaze over high heat, scraping brown bits from bottom and sides of pan. When liquid is reduced by half (about 3 minutes), add mushrooms and cook 2 minutes, stirring.
Add lemon juice and cook 1 minute, stirring. 10. Correct seasonings, pour sauce over meat and garnish with parsley.