1. Cook bacon and chicken in a large skillet, until both are cooked through.
2. While meat is cooking, add lemon juice, olive oil, and dijon mustard to a small mixing bowl. Whisk together, and set aside.
3. Wash and thinly chop lettuce into shreds. Transfer to large mixing bowl. Core and chop apple into ½ inch pieces and add to bowl.
4. When chicken and bacon are done cooking, remove from heat and place bacon on a paper towel or towel to drain excess fat. Chop cooked chicken breasts and bacon into similar sized pieces. Transfer to the bowl with lettuce in it. Top lettuce, chopped apple, and meat with cheddar cheese, pecans, and optional toppings, if desired. Serve with dressing on the side to be dressed individually.