Ingredients

• 4 chicken breasts or 8 boneless thighs
• 3 large onionsyellow, which caramelise most reliably
• 30 g butter
• 1 tbsp olive oil
• 250 ml chicken stock
• 1 tsp Worcestershire sauce
• 1 tsp Dijon
• 140 g Gruyeregrated
• 1 kg Maris Piper potatoesfloury, for luxurious mash
• 80 ml warm milk
• 1 roasted garlic bulb
• 1 1/2 tsp fine salt, plus thyme leaves and black pepper

Method

1. 01

   Caramelise the onions

   Melt the butter with the olive oil in a large frying pan over medium-low heat, add the sliced onions and a good pinch of salt, and cook for 30 minutes, stirring every few minutes and scraping the base, until deep mahogany and jammy. Take out half and reserve.

   30 g butter · 1 tbsp olive oil · 3 large onions

   Thirty minutes for the onionsNo shortcut. Higher heat scorches the edges while the centres stay sharp, and the gravy shows it.

   Keep half the onions backSome in the gravy for body, some on top for texture. All simmered in and you lose the strands.

2. 02

   Roast the garlic and start the potatoes

   While the onions cook, roast the garlic bulb at 190 C for 35-40 minutes until soft, and boil the potatoes in salted water for 18-20 minutes until a knife meets no resistance. Drain and steam dry for 5 minutes.

   1 kg Maris Piper potatoes

3. 03

   Sear the chicken

   Season the chicken and sear it in the onion pan over medium-high heat for 3-4 minutes a side, until golden. The browned base of that pan is the foundation of the gravy, nothing gets washed away.

4. 04

   Build the gravy

   Add the stock, 1 tsp Worcestershire, Dijon, the thyme and the onions from the pan, scraping the base clean. Simmer over medium-low for 12-15 minutes, until the chicken reads 75 C and the gravy is glossy and reduced by about a third.

   250 ml chicken stock · 1 tsp Dijon

5. 05

   Melt the Gruyere

   Cover each piece of chicken with the grated Gruyere and put the pan under a hot grill for 2-3 minutes, until molten and blistered in spots.

   140 g Gruyere

6. 06

   Make the mash

   Mash the potatoes with the warm milk and squeeze in the roasted garlic while the potatoes are still steaming. Hot potato absorbs it, cool mash just carries lumps. Season well.

   80 ml warm milk

7. 07

   Serve

   Spoon the mash onto warm plates, sit the chicken on top and pour over the gravy and the reserved caramelised onions.