Place the peppers, tomatoes, and onion halves in a large cast iron skillet. Broil until the vegetables are deeply charred on all sides, turning every few minutes, about 10–20 minutes.
Transfer the hot vegetables to a large heatproof bowl and immediately cover tightly with plastic wrap. Allow to steam for 15 minutes.
Remove the plastic wrap and peel the skins from the peppers and tomatoes.
Transfer the peeled vegetables to a cutting board and finely chop into a coarse relish-like texture. Place in a large mixing bowl.
Coarsely crush the toasted coriander and caraway seeds using a mortar and pestle.
Add the crushed spices, lemon zest, lemon juice, and olive oil to the vegetables. Season to taste with salt and freshly ground black pepper and mix well.
Transfer to a serving plate. Top with chopped parsley, green olives, and an additional drizzle of olive oil.
