Peel and finely chop the onion. Warm 1 tbsp oil in a pan. Add the onion. Season with salt and pepper. Fry over a lowish heat for 5 mins till it starts to soften. Stir now and then.
While the onion cooks, peel and grate or crush the garlic. Halve the pepper. Scoop out the seeds and white bits. Roughly chop it. Peel the potatoes. Chop into bite-size pieces.
Stir the garlic, pepper and potatoes into the onion. Cook for 3-4 mins till the pepper starts to soften. Stir every so often.
While the other veg cook, trim the ends off the aubergine. Chop into fairly small pieces. Add to the pan. Stir and fry for 3-4 mins till everything s soft and glossy.
Stir the tinned cherry tomatoes into the pan. Add 150ml boiling water. Cover and simmer over a medium-low heat for 15-20 mins till the cianfotta has thickened slightly and the potatoes are tender. Stir every so often while it cooks.
Stir in the olives and 1 tbsp balsamic vinegar. Taste and add salt, pepper or a splash more water if you think it needs it.
Ladle the cianfotta into warm bowls. Top each with 3 tbsp ricotta and a handful of rocket. Serve straight away.