Heat the oil in a frying pan over medium heat. Peel the garlic cloves. Here’s a tip for easy peeling: put the clove flat on a chopping board and take a wide, blunt knife and place it, flat-side down, on top of the clove and push down hard with your hand. This loosens the skin and makes peeling easier. Add the cloves, along with chilli, if using, and leave to infuse the oil for 3–4 minutes.