When the onions and courgettes are tender, stir in the cooked aubergines and peppers and the chopped tomatoes. Add a little more seasoning and 150ml water. Bring to a simmer and cook gently until the mixture has thickened so that you can draw a wooden spoon across the base and leave a channel for a few seconds.
Sterilize 3-4 jam jars with lids while your vegetables are cooking by washing them in hot soapy water and then putting them in a cool oven (100C) to dry for 30 minutes.
Put the hot vegetable mixture in a food processor but take the bay leaves out first. Whizz until smooth and pour the mixture into the sterilized jam jars. Obviously be very careful when you’re doing this as the mixture is still hot. Seal the jars at once with the lids and let them cool.
Once cool, store in the fridge or a cool larder and eat up!