Preheat the oven to 200C/400F/Gas 6.
For the garlic roast chicken, place the chicken into a roasting tin. Cut the lemon in half and squeeze the juice over the chicken, then rub the chicken with the rock salt.
Place the garlic, squeezed lemon halves and onion into the chicken cavity. Season the chicken all over with freshly ground black pepper and drizzle over a little olive oil.
Transfer to the oven and roast for 1¼ hours, or until the juices run clear when the chicken is pierced with a skewer and it is completely cooked through. Remove from the oven and allow to rest in a warm place for a few minutes before serving.
For the honey-glazed baby veg, heat the butter in a pan until it foams, then add the caraway seeds, thyme and vegetables. Stir well and season with salt and freshly ground black pepper.
Add the honey and bring to the boil. Reduce the heat and simmer, stirring occasionally, until all the vegetables are coated and the honey has thickened.
Just before serving, take some of the roasted garlic from inside the chicken cavity and squeeze out of its skin over the vegetables. Drizzle over the balsamic vinegar and stir well.
To serve, carve the chicken into portions and place onto serving plates with the honey-glazed baby veg.