Step 1

Use a small knife to cut a shallow cross in the base of each tomato. Place half the tomatoes in a large heatproof bowl. Cover with boiling water. Set aside for 2 minutes. Use a slotted spoon to remove, then repeat with the remaining tomatoes. Peel off the skin. Cut in half crossways. Remove the seeds and roughly chop the flesh. Place with the juices in a large bowl.

Step 2

Heat the oil in a large saucepan over medium heat. Add onion and cook, uncovered, stirring occasionally, for 3 minutes or until slightly soft. Add the chillies and garlic, and cook, stirring, for 1 minute. Add the tomatoes, tomato paste and sugar, and stir to combine. Cover and bring to the boil. Reduce heat to low and cook, covered, stirring often, for 20 minutes.

Step 3

Add the eggplant to the pan and stir to combine. Increase heat to high, cover and return to the boil. Reduce heat to low and cook, covered, stirring occasionally, for 20 minutes or until the eggplant is very soft.

Step 4

Stir the basil into the sauce. Taste and season with salt and pepper, and a little extra sugar if necessary. Transfer to a large bowl and set aside for 10 minutes to cool slightly. Cover and place in the fridge for 30 minutes or until cooled completely.