Squirt low-calorie cooking spray a couple of times into a non-stick frying pan and fry the onion and garlic for a couple of minutes on medium heat. The onion should be just turning translucent.

Next, add the chillies, reducing the heat to low. Cook for a further ten minutes, until tender, stirring regularly to avoid the mixture sticking.

Finally, add the sweetener and balsamic vinegar, seasoning to taste. Cool and enjoy within five days.