Heat the slow cooker. Melt the butter in a frying pan and quickly brown the chicken thighs all over. Make sure the skin picks up plenty of colour. Season, then put them in the slow cooker. Brown the spring onions and add them to the slow cooker as well. Add the stock, mustard and honey and cook on low for 4 hrs.
Stir in the cream or cre?me frai?che and peas, then cook for a further 15 mins with the lid off. Re-crisp up the chicken skin under the grill, if you like.