Melt half the butter in a pan over a medium heat or in the pressure cooker until sizzling. Season and brown the chicken for 8-10 mins before removing to a plate. Heat the rest of the butter in the pan and stir in the onions. Cook for 5 mins, until soft, then add the garlic and bay leaves, and cook for 1 min. Stir through the carrots, leek and potato, so everything is coated in the buttery juices, and leave to cook for 2 mins to soften slightly.

Scatter over the flour and stir to make a sandy paste that covers everything, then leave to cook for 2 mins more. Splash in the wine or cider, if using, and simmer for 3-4 mins, then pour over and stir through the stock. Return the chicken to the pan, season with salt and pepper and bring to a simmer. Give everything a good stir, then lock in the lid, bring to high pressure, and cook for 5 mins. Leave the pressure to drop gradually. Check the potatoes are cooked with the point of a knife – if not, simmer for a few minutes more with the lid off. Stir in the mustard and herbs, then serve. The stew can be made ahead and kept chilled for two days or frozen for three months if you leave out the herbs. Defrost and reheat in a pan over a medium heat until piping hot, then finish with the herbs.