01 -
Cut the tomatoes into ½-inch thick slices and arrange in a single layer in a large, shallow dish.
02 -
Combine oil, vinegar, onion, garlic, parsley, basil, salt, and pepper in a jar with a tight-fitting lid. Shake vigorously until well mixed.
03 -
Pour marinade evenly over the tomatoes. Cover and marinate for 2 to 3 hours at room temperature, or 12 to 24 hours in the refrigerator.
04 -
If refrigerated, bring tomatoes to room temperature before serving. Transfer to serving dishes, spoon marinade juices over the tops, and garnish with additional chopped fresh herbs if desired.