Place each between two pieces of plastic wrap with the smooth side down. Gently pound each chicken breast with a meat mallet to 1/4-inch thick. In a shallow pie plate, combine flour, salt, and pepper. Roll chicken in flour mixture to coat all sides. In a large nonstick frying pan over medium heat, heat butter and vegetable oil. Add chicken and cook 3 to 5 minutes per side or until fully cooked and tender. Pour lemon juice and white wine over chicken. Add capers and simmer another 2 to 3 minutes longer. Remove from heat and transfer chicken onto a serving platter. Reduce liquid left in frying pan by boiling an additional