Ingredients

Step by step

1. For the herby butter, put the chives and tarragon in a food processor and pulse to break down. Add the mustard, garlic and lemon zest. Pulse again to combine. Add the butter and pulse until incorporated. Stir in the preserved lemon; season with black pepper and lemon juice, to taste.
2. Preheat the oven to 190°C, fan 170°C, gas 5. Carefully work your fingers under the skin at the neck end of the chicken, releasing the skin from the meat so you form a pocket on top of each breast. Using a teaspoon, push the herby butter mixture into the pockets, smoothing the mixture as far up the breast as you can. Tuck the loose neck skin underneath the chicken. Place the garlic bulb halves in the cavity. Place the red onion wedges in a large roasting tin and sit the chicken on top. Season the chicken skin with salt and black pepper.
3. Cover the roasting tin with foil, then roast for 45 minutes. Remove the foil, then roast, uncovered, for 45 minutes or until golden-brown and cooked through, with the juices running clear when you pierce the thickest part of the thigh. Transfer the chicken and onions to a large board and loosely cover with foil while you make the vinaigrette.
4. Pour the roasting juices from the tin into a large saucepan. Add the chicken stock, then set over a medium-high heat and bubble until reduced by half (about 10 minutes). Meanwhile, place the chopped hazelnuts in the chicken roasting tin and toast in the oven for 6-8 minutes until goldenbrown. Pour in 125ml of the sherry vinegar, then set over a high heat on the hob and reduce to a syrup, scraping up the rich chicken sediment from the tray. Add this to the reduced chicken stock and remove from the heat. Whisk in the mustard, followed by the oil, until emulsified. Whisk in the remaining sherry vinegar and season to taste.
5. Carve the chicken, then arrange on a platter with the red onions, spooning over the hazelnut vinaigrette. Scatter with the extra chives and zest and serve with boiled new potatoes, if liked.