This Mary Berry chicken casserole is a deeply comforting dish of tender, fall-apart chicken thighs nestled in a rich, herb-flecked tomato and vegetable sauce that thickens to a glossy, amber-coloured gravy as it slowly cooks in the oven. The sauce clings to every piece of chicken, carrying warm notes of thyme, sweet onion, and a gentle earthiness from the mushrooms. It comes together with straightforward method and no complicated techniques, making it entirely reliable for a midweek supper or a relaxed Sunday dinner. From start to finish, it is ready in around 1 hour 45 minutes.

What sets this version apart is the balance between simplicity and depth of flavour. A short browning stage at the start builds colour and savouriness in the base, while a slow oven finish does the rest of the work without any attention needed.

Ingredients

For the chicken

6 bone-in, skin-on chicken thighs (roughly 1kg total)
1 tbsp plain flour, seasoned with salt and pepper
2 tbsp sunflower oil

For the vegetable base

1 large onion, peeled and roughly chopped
2 medium carrots, peeled and cut into 1cm rounds
2 celery sticks, sliced into 1cm pieces
150g chestnut mushrooms, halved
3 garlic cloves, peeled and finely sliced

For the sauce

400g tin chopped tomatoes
300ml hot chicken stock
1 tbsp tomato puree
1 tsp Worcestershire sauce
1 tsp dried thyme
1 bay leaf
Salt and freshly ground black pepper, to taste

To finish

Small handful of fresh flat-leaf parsley, roughly chopped

How to Make Mary Berry Chicken Casserole Recipe

Preheat the oven: Heat the oven to 180C (160C fan, gas mark 4) and position a rack in the lower middle of the oven.
Coat the chicken: Pat the chicken thighs dry with kitchen paper, then toss them in the seasoned flour until each piece has a light, even coating. Removing surface moisture first helps the flour stick and gives a better colour when frying.
Brown the chicken: Heat the oil in a large, ovenproof casserole dish over a medium-high heat. Add the chicken thighs skin-side down and fry for 4 to 5 minutes without moving them, until the skin is golden and releases cleanly from the pan. Turn and cook the other side for 2 minutes, then transfer to a plate and set aside.
Soften the vegetables: Reduce the heat to medium. Add the onion, carrots, and celery to the same pan and cook for 6 to 8 minutes, stirring occasionally, until softened and beginning to colour at the edges. Cooking in the residual fat from the chicken builds flavour into the base of the sauce without adding extra oil.
Add garlic and mushrooms: Stir in the garlic and mushrooms and cook for a further 2 minutes, until the mushrooms start to give off their liquid.
Build the sauce: Add the tomato puree, stir to coat the vegetables, and cook for 1 minute. Pour in the chopped tomatoes, hot chicken stock, Worcestershire sauce, dried thyme, and bay leaf. Stir everything together, scraping any sticky bits from the bottom of the pan.
Return the chicken and cook in the oven: Nestle the browned chicken thighs back into the casserole, skin-side up, so the tops sit just above the surface of the sauce. Cover with a tight-fitting lid and place in the oven for 50 minutes.
Uncover and finish: Remove the lid and cook for a further 15 minutes, until the chicken skin crisps slightly and the sauce reduces to a glossy, coating consistency. The internal temperature of the thickest part of the thigh should read 75C on a meat thermometer.
Rest and serve: Remove the bay leaf and leave the casserole to sit, uncovered, for 5 minutes before scattering over the fresh parsley and bringing it to the table.

Tips for the Best Mary Berry Chicken Casserole Recipe

Why is my casserole sauce watery instead of glossy and thick?

This usually happens when the lid stays on throughout the entire oven time. Removing the lid for the final 15 minutes allows steam to escape and the liquid to reduce down into a concentrated, coating sauce. If it still looks thin, return it to the hob over a medium heat for 5 minutes with the lid off.

Why does my chicken skin turn soft and rubbery instead of golden?

The skin needs direct, dry heat to crisp. Make sure the chicken thighs are patted completely dry before flouring, the oil is hot before they go in, and the skin side sits above the sauce level when it goes into the oven. If the skin is submerged in liquid, it will steam rather than colour.

Why is my chicken still slightly pink near the bone after the listed cooking time?

Bone-in thighs vary in size, which affects cooking time. Always check the thickest part with a meat thermometer, aiming for 75C. If needed, cover the dish again and return to the oven for a further 10 minutes before re-checking.

Why does my casserole taste flat even after seasoning?

A flat flavour usually points to one of two things: insufficient browning of the chicken at the start, or stock that is too weak. Make sure the chicken develops a deep golden colour before removing it from the pan, and use a good-quality stock rather than an overly diluted one. A final check of salt and pepper just before serving can also lift the whole dish.

Why are my vegetables mushy by the time the chicken is cooked?

Cutting the carrots and celery too small means they break down completely during the long oven cook. Keep pieces to around 1cm and they will hold their shape while still becoming tender. Avoid very fine dicing for any vegetable going into a casserole.

Serving Suggestions

Spoon over creamy mashed potato, pressing it up around the edges of the bowl to catch the sauce
Serve alongside steamed basmati rice for a lighter, weeknight finish
Pair with thick slices of crusty white bread for mopping up the sauce at the table
Add a side of lightly buttered green beans or steamed tenderstem broccoli for colour and bite
Serve in wide, shallow bowls to keep the sauce at the right temperature from start to finish of the meal

Storage

Room temperature

Leave the casserole to cool completely, then transfer to an airtight container and store at room temperature for no more than 2 hours before refrigerating or freezing.

Refrigerator

Once cooled, store in a sealed airtight container in the fridge for up to 3 days. Reheat thoroughly in a covered saucepan over a gentle heat until bubbling, or in the oven at 170C (150C fan) for 20 to 25 minutes. Bring the casserole closer to room temperature before reheating so the chicken warms evenly all the way through.

Freezing

Transfer cooled portions into freezer-safe containers or zip-lock bags, removing as much air as possible, and freeze for up to 3 months. Defrost overnight in the fridge, then reheat as above until the chicken reaches a steaming hot temperature throughout before serving.

Nutrition

Calories: 390 kcal
Carbohydrates: 14g
Protein: 36g
Fat: 21g
Saturated Fat: 5g
Sodium: 520mg

Nutrition values are estimates based on average ingredient weights and may vary depending on the specific brands and serving sizes used.

FAQs

Can I use boneless, skinless chicken thighs instead of bone-in thighs?

Yes, boneless thighs work well and reduce the oven time to around 35 to 40 minutes total. They will not develop a crispy skin, but the meat stays moist and absorbs the sauce well. Reduce the uncovered oven time to 10 minutes to avoid the chicken drying out.

Can I make this chicken casserole ahead of time?

This casserole actually improves overnight. The flavours deepen as it sits and the sauce thickens further in the fridge. Prepare the full recipe up to two days ahead, cool completely, refrigerate, and reheat gently before serving. Add a small splash of stock when reheating if the sauce has thickened too much.

Can I swap the tinned tomatoes for passata?

Passata works as a direct swap at the same 400ml quantity. It produces a smoother, slightly thinner sauce with a more uniform texture. If a chunkier sauce is preferred, stick with chopped tomatoes.

Can I make this chicken casserole in a slow cooker?

Yes. Complete the browning and vegetable softening stages on the hob first, then transfer everything to the slow cooker. Cook on low for 6 to 7 hours or high for 3 to 4 hours. Remove the lid for the last 30 minutes on high to help the sauce reduce slightly, as slow cookers retain all moisture.

Is this recipe suitable for children?

It is suitable for most children. The Worcestershire sauce and seasoning are mild, and the dish contains no chilli or strong spices. For very young children, shred the chicken away from the bone before serving and check the sauce is not too salty by using a reduced-salt stock.

Conclusion

This Mary Berry chicken casserole recipe delivers the kind of straightforward, satisfying cooking that earns a permanent spot in the weekly rotation. Bone-in thighs browned until golden, a vegetable-rich tomato sauce with real depth, and a slow oven finish that makes the kitchen smell extraordinary. The recipe serves 4 to 6 people comfortably, depending on appetite, and scales up easily for larger gatherings by adding two additional thighs and increasing the stock by 100ml.

If this is the first time making it, follow the steps closely, particularly the browning stage and the uncovered final cooking time, and the result will be a glossy, flavourful casserole that needs nothing more than good bread or mashed potato alongside it. Share this recipe with anyone who loves a reliable, crowd-pleasing chicken dinner, and leave a comment below with how it turned out. If you enjoyed this, you might also like the Mary Berry strawberry coulis recipe, a quick, vibrant sauce that works beautifully as a dessert topping.