Heat the oil in a large frying pan over a medium-high heat.
Add the chicken thighs and lightly brown on both sides – this should take about 5 minutes.
Once lightly browned remove from the pan and place in the slow cooker.
Add the butter to the pan and heat until melted.
Add the onion and cook for 5 minutes, stirring occasionally, until softened.
Add in the garlic, stir, and cook for a further minute.
Stir in the flour, salt, pepper, thyme and celery salt. Cook for 2 minutes.
Add the stock and lemon juice. Stir and bring to the boil, then pour into the slow cooker over the top of the chicken.
Add the mushrooms, carrots and celery to the slow cooker and stir.
Place the lid on and cook on a low heat for 5-6 hours or a high heat for 3-4 hours.
Once cooked shred the chicken a little with two forks then stir in the cream.
Serve topped with fresh parsley. I love to serve this casserole with mashed potato and green beans.
Make-Ahead:You can make this dish ahead, then cool, cover and refrigerate for up to 2 days. Heat through in a large saucepan for 10-15 minutes on a medium heat until the chicken is hot all the way through. Add a splash of cream or milk if needed to loosen it up.Freezing:Make the casserole, then cool, cover and freeze. Defrost thoroughly in the refrigerator. Heat through in a large saucepan for 10-15 minutes on a medium heat until the chicken is hot all the way through.Ingredient swaps
I love to use chicken thighs in casseroles, as they're more tender and stand up well to slow cooking. They also shred up beautifully. However you can swap out the chicken thighs for chicken breast, or even bone-in chicken pieces.
Add in extra veggies - such as baby potatoes, leeks, shallots or cubes of butternut squash.
Add crispy bacon or pancetta at the end of cooking for am extra hit of flavour.
How to scale up and scale down this recipeYou can double this recipe with no change needed to the ratios.If you would like to halve the recipe, just halve the amount of chicken and vegetables, keeping the quantities of everything else the same. The casserole needs the amount of sauce in this recipe so it doesn't dry out.Can I cook it in the oven instead?Yes, you can cook in a casserole dish with a lid on, in the oven at 175C/350F for 45-60 minutes, until the carrots are tender. Add approx 120ml (½ cup) extra chicken stock when making the sauce, as liquid evaporates more in the oven. Also, check and stir the dish a couple of times when cooking in the oven.Nutritional information is approximate -based on 4 servings WITHOUT the serving suggestions of mashed potatoes and green beans