Preheat oven to 400°F (205°C). Line a baking sheet with parchment paper or a silpat mat.
In a small bowl, combine the salt, black pepper, hot chilli powder, smoked paprika and garlic powder.
Place chicken breasts onto the baking sheet. Sprinkle the seasoning blend onto both sides of the chicken, rubbing it in.
Bake in preheated oven for 10 minutes.
Remove chicken from oven and spread bbq sauce onto both sides. Return to oven and bake for another 5 minutes.
After 5 minutes, remove chicken from oven and increase heat to 475°F.
Spread more bbq sauce onto both sides of the chicken and bake for a final 5 minutes. Remove from oven and set aside.
ASSEMBLING THE SANDWICHES:
Place a frying pan onto the stove over medium heat. Spread softened butter onto both sides of each burger bun. Place butter side down onto the pan and let it toast for 1-2 minutes, or until golden brown.
Spread more bbq sauce onto the buns. On the bottom bun, place on the lettuce and bbq chicken. Spread more bbq sauce on top of the chicken, if you want.
Top the chicken with sliced mozzarella, bacon, red onions and the top bun. Serve and enjoy!
