Preheat the oven to 400°F (200°C/Gas 6). Put the bulgur wheat in a heatproof bowl, pour over half of the vermouth and cover with boiling water. Set aside until needed.
Heat half of the oil and fry the onion and carrots for 10 minutes, then remove the pan from the heat and stir in the nuts, celery seeds and well-drained bulgur wheat.
Stuff the poussins with the bulgur wheat mixture. Place them in a roasting tin, brush with oil and sprinkle with salt and pepper. Roast for 45—55 minutes until cooked.
Meanwhile, spread out the red onions, aubergines, squashes and baby carrots on a baking sheet.
Mix the corn syrup with the remaining vermouth and oil in a small bowl. Season with salt and pepper. Brush the syrup mixture over the vegetables and roast them for 35-45 minutes until golden. Cut each poussin in half and serve with the roasted vegetables.