Preheat oven to 230°C. Line 2 large roasting pans with non-stick baking paper.
Place the capsicum, eggplant and onion in a bowl. Drizzle the oil over it. Toss to coat. Transfer to the lined trays.
Roast in oven, swapping the trays halfway through cooking, for 40 minutes or until tender and light golden.
Meanwhile, place the burghul in a large heatproof bowl. Bring the stock to the boil in a small saucepan. Pour over the burghul and set aside for 20 minutes or until tender. Drain.
Combine the capsicum mixture and burghul in a bowl.
Add the lemon rind, lemon juice and coriander to the burghul mixture. Season with salt and pepper.
Toss to combine and serve.