1. Sprinkle chicken with 1/2 teaspoon pepper and 1/8 teaspoon salt. Place 2 tablespoons flour in a shallow dish. Dredge chicken in flour. Heat a large skillet over medium-high heat. Add 1 tablespoon oil and 1 tablespoon butter to pan; swirl to coat. Add chicken to pan; cook 5 minutes on each side or until done. Remove chicken from pan; keep warm.
2. Add remaining 1 tablespoon oil to pan; swirl to coat. Add remaining 2 tablespoons flour to pan; cook 30 seconds, stirring occasionally. Add stock to pan; bring to a boil, stirring with a whisk until smooth. Reduce heat; simmer 2 minutes. Stir in 1/4 teaspoon pepper and remaining 1/8 teaspoon salt.
3. Cook potatoes according to package directions. Combine potatoes, remaining 1/4 teaspoon pepper, remaining 1 tablespoon butter, and milk in a medium bowl; mash to desired consistency. Serve with chicken and gravy. Sprinkle with parsley.