Put a frying pan on a medium heat with the olive oil.

Peel and dice the onions in 1cm cubes and add them to the pan, keep stirring.

While frying, deseed the peppers and dice in 1cm cubes.

Once the onions start to be translucent, add the peppers. Keep stirring.

Meanwhile dice the aubergine in 1cm cubes and add it to the pan. Keep stirring.

In the meantime dice the courgette in 1cm cubes. You can peel it first if you prefer. Add it to the pan. Once the courgette is a bit cooked, pour in the chopped tomatoes and add salt.

Keep stirring until the tomatoes are cooked.