Chicken with Beaujolais, Prunes, Shallots and Thyme

1 kg 2lb 4oz whole chicken thighs, legs, drumsticks or breasts
50 g 1¾ oz butter
4 large or 12 small shallots, peeled (leave the root on to help them hold together)
1 tbsp tomato purée, paste
2 garlic cloves, finely chopped
2 thyme sprigs, plus ½ tsp picked thyme leaves
½ bunch flat-leaf parsley, leaves picked and finely chopped and stalks reserved
2 bay leaves
200 ml 7fl oz Beaujolais, or another young, fruity red wine
16 pitted prunes
200 ml 7fl oz chicken stock
1 tbsp Dijon mustard, plus more to serve
salt and freshly ground black pepper

Season the chicken with salt and pepper.
Melt the butter in a casserole pan over a moderate heat. Add the chicken, and fry for around 5 minutes, turning, until golden brown all over. Add the shallots and continue to cook for another 4–5 minutes, until they too have taken on a bit of colour.
Turn down the heat and add the tomato purée (paste), garlic, thyme sprigs, parsley stalks and bay and stir gently. Then add the wine, stirring well to dislodge any bits of caramelized chicken stuck to the pan. Simmer for a few minutes, then add the prunes and the chicken stock. Cook over a low–moderate heat for around 30–40 minutes, until the chicken is tender and cooked through.
Remove the chicken from the pan and leave it to rest on a plate, keeping it warm, while you reduce the liquid in the pan over a high heat for a couple of minutes to thicken it slightly. Add the Dijon and whisk to combine.
Add the chicken back into the sauce in the pan and season well with salt, if needed, and plenty of freshly ground black pepper. Remove from the heat and strew with the chopped parsley and picked thyme leaves, and with more mustard on the side.