Butterfly the chicken breast to an even thickness of around 10-15mm (½") and place them in a sealable bag.
Remove the stems from the chilli peppers and add them to a mini blender.
Roughly chop the onion and place it in the blender.
Peel the garlic cloves and add them to the blender.
Add the remaining ingredients for the marinade to the blender and blitz to form a smooth paste.
Remove 2 tablespoons of the marinade and mix it through the mayonnaise, cover with cling film and place in a fridge until you make the burgers.
Add the remaining marinade to the chicken breasts. Massage the marinade into the chicken and place it in the fridge for at least 1 hour.
Heat a griddle pan over a medium-high heat and brush it lightly with a little neutral cooking oil.
Remove the chicken breasts from the marinade and place them in the pan, and cook for 6-8 minutes per side, or until the internal temperature reaches 73°C or 165°F.
Slice the tomato and red onion.
Remove the chicken and set them aside, and griddle the burger buns to pick up any residual flavour from the pan. This will take no longer than 90 seconds.
Build your sandwich, I like to start with spicy Peri Peri mayonnaise on the base, followed by lettuce, a slice of tomato, and then the smoked cheese. Finally, add the chicken breast, more mayo and some red onion rings.