Cook chicken breast over medium heat in a pan heated with a dash of oil. Once cooked, slice into thin strips or shred.
Prepare Apple Cabbage Slaw: Chop cabbage, red bell pepper, apple, and green onion into thin matchsticks. In a small bowl, mix apple cider vinegar, mayonnaise, and mustard. Pour over slaw mixture and stir until evenly distributed.
Assemble Sandwiches to Cook: Between two pieces of bread, layer 2 slices of cheese, 1/4 of an apple (sliced), and 1/4 c of chicken breast (sliced/shredded), and 1/4 teaspoon of rosemary. Cook in the oven, on the stove top with a frying pan, or in a sandwich press until golden, about 5 minutes.
When sandwich is done cooking and the cheese inside is melted and gooey, add 1/3 c of the Apple Cabbage Slaw and enjoy!