Set oven to broil. Wash and trim chili peppers, then place them on a baking sheet.
Pop peppers into the oven and broil on high until the top of the outside is black and blistered – mine usually take about 10-12 minutes.
Gently tug on the stems – the tops will come right off. Then pinch the blistered skin and peel it away. If desired, de-seed them to reduce the heat of the final product. (I didn’t and my sauce wasn’t overly spicy, but I sometimes do if the peppers are particularly hot.)
Add peppers, vinegar, lime juice, sweetener (rapadura, honey, or maple syrup), salt and four cloves of garlic to a food processor and puree until smooth.
Taste and add optional cayenne pepper and additional salt and sugar, and extra cloves of garlic if desired.
Transfer mixture to a clean jar with a tight-fitting lid and store in the fridge for up to one month.