Scatter the beetroot wedges in a shallow roasting tin. Drizzle with 1 tablespoon of the oil and a little salt and pepper. Cover with foil and place on the upper rack of the halogen oven.
Set the temperature to 250°C (482°F) and cook for about 45 minutes, uncovering for the final 10 minutes, until the beetroot is tender. While cooking, mix the remaining oil with the vinegar, rosewater, garlic and chopped herbs. Season with salt and pepper. Put the couscous in a heatproof bowl, add the hot stock and cover with foil. Leave to stand for 10 minutes until the couscous has absorbed the stock.
Fluff up the couscous grains with a fork and stir in the dressing and pine nuts until evenly mixed. Lightly stir in the beetroot. Serve with roast duck or chicken.