For peri-peri sauce, place all ingredients into a food processor and blitz until finely chopped.
Transfer into a medium saucepan and simmer for 20 minutes.
Add lemon juice, taste and adjust seasoning to taste.
Pour into a jar, cover with a 2cm layer of olive oil, seal and store in the refrigerator.
Mix together the slaw ingredients in a medium bowl and season to taste with salt and pepper.
Mash the avocado in a small bowl and season.
Mix 2 tsp of peri-peri sauce with the mayonnaise in a small bowl.
Slice each chicken breast in half horizontally, place between 2 sheets of clingfilm and pound with a meat mallet until of even thickness.
Marinate the chicken in peri-peri for at least 30 minutes.
Preheat a BBQ to high, grill the chicken until charred and cooked through and toast the burger buns.
To assemble, spread the avocado onto the bases, top with two pieces of chicken, followed by slaw, drizzle with mayonnaise and place the burger dome on top.
