Slow-cooker chicken casserole

Ingredients
knob of butter
½ tbsp rapeseed or olive oil
1 large onion, finely chopped
1 ½ tbsp flour
650g boneless, skinless chicken thigh fillets
3 garlic cloves, crushed
400g baby new potatoes, halved
2 sticks celery, diced
2 carrots, diced
250g mushrooms, quartered
15g dried porcini mushroom, soaked in 50ml boiling water
500ml stock made with 2 very low salt chicken stock cubes (we used Kallo)
2 tsp Dijon mustard, plus extra to serve
2 bay leaves

Method
STEP 1
Heat a knob of butter and ½ tbsp rapeseed or olive oil in a large frying pan, cook 1 finely chopped large onion for 8-10 mins until softened and starting to caramelise.

STEP 2
Meanwhile, put 1 ½ tbsp flour and a little salt and pepper in a bowl and toss 650g boneless, skinless chicken thigh fillets in it.

STEP 3
Add 3 crushed garlic cloves and the chicken to the pan and cook for 4-5 mins more until the chicken is starting to brown.

STEP 4
Transfer to your slow cooker, along with 400g halved baby new potatoes, 2 diced celery sticks, 2 diced carrots, 250g quartered mushrooms, 15g dried and soaked porcini mushrooms with the 50ml soaking liquid, 500ml chicken stock, 2 tsp Dijon mustard and 2 bay leaves.

STEP 5
Give it a good stir. Cook on Low for 7 hours or High for 4 hours.

STEP 6
Remove the bay leaves and serve with a little Dijon mustard on the side.