1.Quarter capsicums, discard seeds and membranes. Cook capsicum, eggplant and onion, in batches, on heated oiled barbecue until browned. Cover capsicum in paper or plastic for 5 minutes then peel away skin.
2.Meanwhile, make creamy horseradish dressing. Blend or process egg, horseradish, honey and garlic until smooth. With motor operating, add oil in a thin, steady stream until dressing thickens slightly.
3.Combine cheese, watercress and tomato in medium bowl, divide among serving plates. Top with capsicum, eggplant and onion, drizzle with dressing.
Make sure you use prepared white horseradish in the dressing and not the blended condiment sold by the name of horseradish cream.