Preheat the oven to 450°F/230°C. Line a baking tray with parchment paper and drizzle with a little oil.
Add the bell peppers whole (pierce them a few times with a sharp knife).
2 red bell peppers
Cut eggplants in half lengthways and place cut side down on the tray. Slice the onions in half and add then cut side down.
2 eggplants, 2 onions
Drizzle veg with remaining olive oil and season to taste with salt and pepper.
2-3 tablespoons extra virgin olive oil, Salt and freshly ground pepper
Bake for around 20 minutes, then turn the bell peppers and bake for another 20 minutes.
Remove the tray of veg from the oven and use cooking tongs to place cooked bell peppers into a large bowl and cover (optionally put them in a plastic bag).
Allow around 10 minutes for the peppers to cool enough to touch then remove and discard the skin, stalk, and seeds. Add the pepper pulp to a bowl.
Next, use a spoon to scrape away the eggplant skin and add the pulp to the bowl with the pepper. Discard the skin and stem.
Finally, chop the cooked onion into strips and add them to the bowl. Add the crushed garlic and chopped parsley.
1 small handful of fresh parsley
Add sherry vinegar and drizzle some of the cooking juices from the tray into the bowl (optionally, add more olive oil). Season with salt, pepper, and some fresh chopped parsley.
2 tablespoons sherry Vinegar, 3 garlic cloves
Mix well, cover, and refrigerate for at least one hour (Optional - this helps the flavors to meld).
Serve alongside your favorite main, with other tapas dishes, or with plenty of fresh bread.