Make marinade by mixing the lemon juice, orange zest, olive oil, rosemary, thyme, salt and pepper in a small bowl.
Rub marinade on chicken and put the chicken in the refrigerator to marinate for at least 6 hours.
Heat up a grill or saute pan with a little olive oil. Brown the chicken slowly for 4 to 5 minutes.
Put whole thyme and rosemary on the baking tray. Slice another lemon and place it in the bottom of the tray with the herbs.
In a measuring cup, add the piri piri chilis, the crushed garlic cloves, the chopped cilantro stalks, the lemon zest without the white part, the sweet bell pepper and cover generously with olive oil. With a hand blender, blend all the ingredients.
Remove the chicken from the plate and place on the tray. Brush the chicken with the Piri Piri sauce.
Bake the chicken at 200°C/200°F for 45 minutes to 1 hour, brushing the sauce on the chicken every 15 minutes.
When the chicken still has 15 minutes left to cook, bake frozen potato wedges on a separate baking sheet.
When the chicken is cooked through (about 45 mins - 1 hr), take the chicken out of the oven and brush it one last time with Piri Piri sauce.