Roast the whole bell peppers in the oven for 20 minutes. Chop and deseed once they are done roasting.
Meanwhile, boil a small pot of water. Pierce the tomatoes with a fork and submerge them in boiling water. A minute later, drain away the water, submerge them once more in cold water, and peel.
Cut the eggplants and zucchinis into thin slices, around 2-3mm in thickness. Add to a non-stick frying pan and fry for a couple of minutes on each side, until lightly browned.
Add the tomatoes, lemon juice, garlic and basil into a food processor or blender, and blend until smooth.
Line a bread tin with plastic wrap, ensuring that there is some excess over the edges. Layer on the eggplants so that they cover the entire bottom of the tin. Add a layer of the tomato sauce and layer on the zucchini, then repeat with the peppers and eggplants until you have ran out of vegetables. Wrap the plastic wrap tightly around the top and leave in the fridge overnight under a weight, to hold it all together. Serve.