Pre-heat oven to 450° and line a baking pan with aluminum foil. Combine eggplant, red onion and garlic in a bowl. Toss with olive oil and tomato paste until vegetables are well-coated. Spread evenly on baking pan and roast for 25 minutes. Remove baking pan from oven and return roasted eggplant mixture to the mixing bowl. Add chopped parsley, red wine vinegar, capers and salt. Blend well with a wooden spoon, breaking up softened eggplant. Final jam should be thick, but easily spreadable.