* 6 red spring onions, trimmed
* 6 green salad onions, trimmed and split lengthways
* 250g small or baby (pearl) onions, peeled and left whole
* 2 pink onions, sliced horizontally into 5mm (1/4in) rounds
* red onions, sliced into wedges
* 2 small yellow onions, sliced into wedges
* 4 banana shallots, halved lengthways
* 200g shallots, preferably Thai
* 3 tbsp olive oil, plus extra for drizzling
* juice of 1 lemon
* 3 tbsp chopped fresh flat leaf parsley
* 2 tbsp balsamic vinegar
* salt and ground black pepper
* kuchai flowers (optional), to garnish
1. Prepare the barbecue. Spread out the onions and shallots in a large flat dish. Whisk the oil and lemon juice together and pour over the mixture. Turn the onions and shallots in the dressing to coat them evenly. Season to taste.
2. Once the flames have died down, position a grill rack over the coals to heat. When the coals are medium-hot, or covered in a moderate coating of ash, place a griddle or perforated metal vegetable basket on the grill rack to heat, rather than cook directly on the rack and risk losing onions through the gaps in the rack.
3. Grill the onions in batches, for five to seven minutes, turning them occasionally. As each batch of onions is cooked, lift them on to a platter and keep hot.
4. Just before serving, add the parsley and gently toss to mix, then drizzle over the balsamic vinegar and extra olive oil.
5. Garnish with a few kuchai flowers, if you like, and serve with warmed pitta bread and grilled haloumi for a vegetarian starter or with grilled meat or fish as a main course.
When available, scatter the whole salad with a few kuchai flowers. These are the lovely blossoms of the evil-smelling Chinese chive. They are available all year round and are sold in Thai food stores.
More recipes from Grill
Grill by Linda Tubby, published by Aquamarine, £8.