Method:

1. Heat the oven to 190°C Fan/200°C Standard.
2. Halve the sprouts, and finely slice the red onion so it's in half circles.
3. Slice the leek into 1.5cm round slices, the celery into thin slices and smash the garlic.
4. Place everything in a shallow ceramic ovenproof dish and garnish with 4 of the thyme stems.
5. Check the chicken thigh skin is dry and pat with kitchen paper if necessary, add the thighs to the top of the dish and season generously with salt and pepper. Add the remaining thyme leaves by breaking them off the stem.
6. Distribute the fat over the chicken and underlying vegetables evenly.
7. Place in the hot oven for 15 minutes until the skin starts to brown on the chicken.
8. While waiting, empty a pouch of chilled chicken broth into a pan and heat on the hob until just boiling. Turn it down to a simmer.At this point if you want a thickish sauce stir up the flour and water in a dish until it's a loose paste (slurry) then pour it into the simmering broth and stir.
9. Take the dish out of the oven and pour the hot broth in between the chicken and into the roasting vegetables. Try and avoid the chicken skins as you want these to crisp up.
10. Cook for a further 30-40 minutes, checking the chicken and veg are browning but not burning.
11. Once the chicken skin is perfectly crispy, remove from the oven and allow to cool slightly.
12. Strip the chicken off the bone on a chopping board with a fork
13. In a shallow bowl, layer the veg, sauce and some mash. Place the chicken on top. The sauce should be sweet, slightly sticky, flavoursome and nourishing. Perfect.