- 12 free-range chicken thighs, skin off, and off the bone
- 500ml (18fl oz) good-quality fresh chicken stock
- 3tbsp Dijon mustard
- 2tbsp crème fraîche
- 20g (¾oz) tarragon, chopped
- 5tbsp breadcrumbs
- 3tbsp chopped parsley
- 125g (4½oz) Gruyère, grated
- you will need
- 1-litre (1¾pt) gratin dish, 5cm (2in) deep
Place the chicken thighs into a large, lidded sauté pan and add the stock. Bring to a very gentle simmer, cover and allow to simmer for 20 to 25 minutes, until the thighs are cooked through. Remove the thighs, turn up the heat and reduce the stock by half. Chop up the chicken into bite-sized pieces. Heat the oven to 180C, 160C fan, 350F, gas 4.
When the stock has reduced, stir through the Dijon and crème fraîche, and add the tarragon. Put the chicken back in the pan, check the seasoning and transfer to the gratin dish. Scatter over the breadcrumbs, parsley and Gruyère and bake in the centre of the oven for 30 minutes until crispy and golden, with the sauce bubbling through. Allow to stand for 5 minutes before serving.
To freeze: Freeze for up to a month, but freeze the topping separately. Defrost in the fridge for 24 hours, gently reheat on the hob, place in the gratin dish and add the topping from frozen then bake at 200C, 180C fan, 400F, gas 6 until browned and bubbling, around 10 to 15 minutes. Serve with a salad of chicory leaves drizzled with a little lemon juice, to counterbalance the richness of the gratin.