Preheat the oven to 375°.
Chicken: Remove the chicken breasts from the marinade and season them on both sides with salt and pepper.
Heat a very large frying pan over medium-high heat and add in the chicken breasts. Cook for 3 to 4 minutes, or golden brown and then flip the chicken over and add the pan to the oven and cook for 8 to 10 minutes or until browned and cooked throughout. Rest for 2 to 3 minutes on a cutting board before slicing.
Onions: Place the onions on a sheet tray and place in the oven at 375° for 30 minutes.
In a medium bowl whisk together the balsamic vinegar, olive oil, and sugar and baste the onions using a brush every 5 minutes. Remove the onions once they are done cooking.
Spread: Whisk together the mayonnaise, Asiago cheese, tomato paste, red wine vinegar, sun-dried tomatoes, basil and salt, and pepper until combined. Cool before serving.
Chicken Club Assembly: Toast 3 pieces of Cobblestone Million Dollar White bread and layer the sandwich as followed: mozzarella cheese, sliced chicken breasts, balsamic onions, lettuce, tomato, toast, mashed avocado, bacon, ham, microgreens, spread, toast.
Chicken Melt Assembly: Place the slices of Million Dollar White bread on a griddle. Once brown flip over and add cheese to each slice. Layer on as followed: bacon, Canadian bacon, sliced chicken breasts, onions, and spread and place on the other sliced of toasted cheese melted bread.