Blend all of the sauce ingredients together in a food processor or blender. Refrigerate until ready to use.
For sous vide chicken
Brown chicken on both sides in a medium hot skillet. Allow to cool.
Rub chicken with Peri Peri Sauce and seal using your preferred method (Ziploc or vacuum seal)
In a sous vide set to 74° Celsius/165.2° F, submerge the sealed chicken and cook for 8-10 hours. After removed from bag, drizzle with oil and season with salt and pepper.
For slow cooker chicken
Brown chicken on both sides in a medium hot skillet.
Place chicken, skin side up, in your slow cooker and cover with sauce.
Cook on LOW for 8-9 hours, HIGH for 4-5 hours (or until done).
For grilled chicken
Cover chicken with marinade in a container. Refrigerate 4-6 hours (to help retain moisture from grill heat)
Prepare your grill to medium-hot heat and add a disposable aluminum pan under the grill rack over indirect heat (keep a burner unlit, if using gas. If charcoal, arrange coals to just one side of the grill)
Remove chicken from marinade and place on grill rack directly over the aluminum pan. Cover grill and grill–turning often–until chicken is done.