For the burgers:
- Slice each chicken breast in half thickness-wise, then cut each fillet in half lengthwise to get 8 pieces. Using a meat tenderizer or rolling pin, lightly pound the fillets.
- In a bowl, mix the chicken with the barbecue sauce and let rest at room temperature while preparing the slaw.
Note : The chicken should be tempered before grilling, but you can also refrigerate it and let it marinate for up to 3 hours. Bring to room temperature 20 minutes before cooking.
For the slaw:
- In a bowl, combine the red and green cabbage, tomatoes, carrot, onion, jalapeño, and cilantro.
- In another bowl, mix the sour cream with mayonnaise, milk, lime juice, sugar, tomato paste, vinegar, garlic powder, chipotle chili, and salt. Taste and adjust seasoning if necessary.
- Pour the dressing over the slaw and mix to combine well. Let sit while preparing the burgers. (The slaw can be made up to 3 hours ahead.)
To assemble the burgers:
- Preheat the barbecue to 200°C (400°F).
- Place the chicken fillets on direct heat, then reduce the flame to low. Cook each side for 3 to 4 minutes.
- Transfer the cooked chicken to a plate and place slices of Bergeron Classique Fumé cheese over each piece. Allow to melt slightly.
- Spread the buns with butter and grill until golden.
- Spread the bottom of the buns with ranch dressing. Stack two pieces of chicken on each bun, top with the slaw and crispy onions. Close the burgers and serve immediately.