Quick and Easy Chicken

2 tablespoons olive oil, 1 onion, chopped, 4 skinless, boneless chicken breast halves, 3 tablespoons ketchup, 3 tablespoons white sugar, 2 tablespoons soy sauce, 2 tablespoons lemon juice, 1 teaspoon ground black pepper

1. Warm oil in a large skillet over medium heat. Sauté onion in oil until translucent, 3 to 4 minutes.
2. Add chicken to onion in the skillet; cook until chicken is lightly browned, 1 to 2 minutes per side.
3. Combine ketchup, sugar, soy sauce, lemon juice, and pepper in a bowl; mix well. Pour over chicken; bring to a boil, then reduce heat.
4. Cover and simmer until chicken is no longer pink in the center and the juices run clear, 25 to 35 minutes. An instant-read thermometer inserted into the center should read at least 165 degrees F (74 degrees C).