Turn the oven to max, grill-broiler on.

Take an oven-proof dish and place the halved pepper skin side up. Place in the broiler rack and cook until skin is charred/blackened. Place the peppers in a plastic zip bag, seal and allow to steam and smoothed for 10 minutes.

Remove the peppers from the bag to a chopping board and peel their charred skin, then roughly chop and add into a blender. Add the oil, garlic, vinegar, salt and pepper and purée until smooth. Transfer to bowl, cover and refrigerate until ready to use.