Creamy Chicken and Mushroom One Pan Casserole
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I still remember the first time I made this creamy chicken-and-mushroom one pan casserole — the kitchen smelled like a cosy bistro and the whole family cleared their plates. It’s a forgiving, stick-to-your-ribs meal that works for busy weeknights, potlucks and chilly Sunday dinners. If you like rich, saucy chicken dishes, this is a recipe you’ll come back to; it’s similar in comfort to a chicken and spinach in creamy mushroom sauce but with an easy one-pan casserole twist.
Why you’ll love this dish
Comforting, practical and crowd-pleasing — this casserole checks a lot of boxes. The sauce is velvety thanks to a classic roux and cream finish, the mushrooms add earthiness, and browning the chicken first locks in flavor. It’s forgiving for cooks of any level and scales well for guests or leftovers.
“Creamy, hearty and easy to make — this one-pan casserole is my go-to for weeknight dinners when I want everyone happy and warmed through.” — home cook review
Reasons to try it:
- Low fuss: most of the work is browning and simmering in one pan.
- Family-friendly: mild, creamy flavors kids tend to enjoy.
- Budget smart: chicken breasts keep costs reasonable and bulk easily feeds more mouths.
- Make-ahead friendly: flavours develop overnight, so it’s great for prepping ahead.
Step-by-step overview
Before you dive into ingredients, here’s the process in a glance so you know what to expect:
- Toss chicken in seasoned flour and brown in batches — this gives texture and flavor.
- Sauté onions, garlic and thyme, then add more flour to build a roux.
- Gradually whisk in chicken stock and milk to make a smooth sauce.
- Add lemon for brightness, fold in mushrooms and the browned chicken, then simmer.
- Finish with double cream (and optional slurry) to reach your preferred thickness.
- Serve with mashed potatoes and vegetables.
What you’ll need
- 5 chicken breasts (1 kg / 2.25 lb), chopped into big chunks or strips
- 45 g (6 tbsp) plain (all-purpose) flour (for coating)
- 1/2 tsp salt (for coating)
- 1/2 tsp black pepper (for coating)
- 2 tbsp oil (vegetable or light olive oil)
- 2 tbsp unsalted butter
- 3 small-to-medium onions, peeled and finely diced
- 5 cloves garlic, peeled and minced
- 1 tsp dried thyme
- ½ tsp celery salt (optional)
- 25 g (3 tbsp) plain (all-purpose) flour (for sauce)
- 1 litre (4 1/4 cups) chicken stock
- 300 ml (1 1/4 cups) milk (whole or semi-skimmed)
- 2 tbsp freshly squeezed lemon juice (juice of approx. 1 lemon)
- 20 chestnut mushrooms, thickly sliced (or cremini/white mushrooms)
- 1/2 tsp salt (for the casserole)
- 1/2 tsp pepper (for the casserole)
- 240 ml (1 cup) double (heavy) cream
- 2 tbsp cornflour (mixed with 5 tbsp cold water to make a slurry) — optional (cornstarch in the USA)
- Small bunch parsley, chopped (for finishing)
- To serve: mashed potatoes, sprouts, peas, sweetcorn
Notes and swaps:
- Use chicken thighs if you prefer darker meat — they add richness and stay moist.
- Swap double cream for crème fraîche or half cream + Greek yogurt (stir in off the heat) for tang.
- If you want a dairy-free version, use a plant-based cream and a starchy milk alternative, but the texture will differ.
How to prepare it
- Put the chicken in a bowl. Add 45 g (6 tbsp) flour, 1/2 tsp salt and 1/2 tsp black pepper. Toss until the chicken is evenly coated.
- Heat 2 tbsp oil in a large frying pan over high heat. Brown the chicken in two batches so pieces get color. They don’t need to be cooked through. Remove with a slotted spoon and set aside.
- Lower the heat to low–medium. Add 2 tbsp butter to the same pan and let it melt. Add the diced onions, minced garlic, 1 tsp dried thyme and optional ½ tsp celery salt. Cook for about 5 minutes until the onions soften.
- Sprinkle 25 g (3 tbsp) flour over the onions. Stir constantly for about a minute — it will form a lumpy paste (that’s fine).
- Pour in a small splash of the 1 litre chicken stock and whisk to combine, breaking up lumps. Continue adding stock a little at a time while whisking until all the stock is incorporated and the sauce is smooth (the onions will still make it look textured).
- Stir in 300 ml milk and keep stirring over the heat until the sauce thickens. Add 2 tbsp lemon juice.
- Add the sliced mushrooms and the browned chicken back to the pan. Season with 1/2 tsp salt and 1/2 tsp pepper. Cover with a lid and simmer gently on the hob for 20 minutes.
- Alternatively, transfer to a casserole dish, cover with foil and bake at 175°C/350°F (fan) for 30 minutes.
- Remove the lid and stir in 240 ml double cream. Heat through for another 5 minutes (or return to the oven uncovered if you used the oven method).
- If you want a thicker sauce, gradually stir in the cornflour slurry (2 tbsp cornflour + 5 tbsp cold water) a spoonful at a time until you reach the desired consistency.
- Finish with chopped parsley and serve with mashed potatoes and your favourite veg.
For another comforting casserole idea, you might like this creamy chicken and spinach casserole that uses similar principles.
How to serve: Best ways to enjoy it
- Classic plate: a generous ladle over a mound of buttery mashed potatoes, with peas, sprouts and sweetcorn on the side.
- Family-style: serve straight from the pan or casserole dish with a crusty loaf for mopping up sauce.
- Lighter option: pile it on steamed rice or buttered egg noodles.
- Garnish: scatter chopped parsley and a little lemon zest to brighten the creamy sauce just before serving.
Storage and reheating tips
- Fridge: Cool within 2 hours and store in an airtight container for up to 3–4 days.
- Freeze: Portion into freezer-safe containers and freeze for up to 3 months. Thaw overnight in the fridge before reheating.
- Reheat: Gently reheat on the hob over low heat, stirring occasionally, until piping hot throughout (internal temperature 75°C / 165°F). In the oven, cover with foil and heat at 160°C/325°F until hot.
- Safety note: Don’t reheat more than once. If sauce has thickened after refrigeration, stir in a splash of stock or milk while reheating.
Pro chef tips
- Brown well: Don’t crowd the pan when browning chicken — you want color, not steam.
- Roux consistency: When you add the second batch of flour to the onions, let it cook briefly to remove the raw flour taste before adding stock.
- Whisk in stages: Adding stock bit by bit prevents lumps and makes a silkier sauce.
- Lemon balance: The lemon juice cuts through the cream. Taste before serving and adjust — a little more if the sauce is too rich.
- Faster option: Use pre-sliced mushrooms and pre-diced onions to cut prep time.
- Want more depth? Add a splash (1–2 tsp) of Worcestershire sauce or a teaspoon of mustard when you add the cream.
For ideas that play with the same comforting flavours but in a soup format, check out this comforting chicken gnocchi soup.
Creative twists
- Mushroom mix: Use wild mushrooms (porcini, shiitake) for a deeper, woodsy flavour.
- Herb swap: Fresh tarragon or parsley works well instead of thyme.
- Add veg: Stir in diced carrots or peas with the mushrooms for extra color and nutrition.
- Cheesy topping: Transfer to an ovenproof dish, scatter grated cheddar, and broil for a minute for a bubbly top.
- Lighter version: Replace some cream with Greek yogurt off the heat for tang and fewer calories.
Your questions answered
Q: Can I use frozen chicken or mushrooms?
A: Thaw frozen chicken fully before browning so it sears rather than steams. Frozen mushrooms can be used but drain well and brown them first to remove excess moisture.
Q: How long does it take from start to finish?
A: Active prep is about 20–30 minutes (chopping, browning). Simmer time is 20 minutes on the hob or 30 minutes in the oven, so plan roughly 50–60 minutes total.
Q: Can I make this ahead for a dinner party?
A: Yes. Make the casserole up to the point of adding cream, cool, refrigerate overnight, then reheat and stir in the cream just before serving. This keeps the texture fresh.
Q: What thickens the sauce if I don’t want to use cornflour?
A: Reduce the sauce by simmering a few extra minutes, or use an extra tablespoon of flour in the roux. Butter + flour roux is effective and traditional.
Q: Is this kid-friendly?
A: Very much so — the mild, creamy sauce and tender chicken are usually popular with kids. Serve with mashed potatoes and peas for a familiar plate.
Conclusion
If you want the original inspiration and step-by-step photos, see the detailed version at Creamy Chicken and Mushroom One Pan Casserole. For a related casserole that pairs chicken with rice and canned mushroom soup, read the Kitchn’s take on Chicken and Rice Casserole With Cream of Mushroom Soup Recipe. If a video walkthrough helps, Natasha’s Kitchen has a clear, visual guide at Creamy Chicken Casserole (VIDEO). And for another one-pan approach with slightly different seasoning, Drizzle and Dip’s recipe is worth a look: One pan creamy chicken & mushrooms recipe.
Internal links used earlier in the article:
- chicken and spinach in creamy mushroom sauce (intro)
- creamy chicken and spinach casserole (ingredients reference)
- comforting chicken gnocchi soup (tips/variations)
Enjoy — and don’t skip the lemon at the end; it really lifts the whole dish.
Creamy Chicken and Mushroom Casserole
Ingredients
Method
- Put the chicken in a bowl. Add 45 g (6 tbsp) flour, 1/2 tsp salt and 1/2 tsp black pepper. Toss until the chicken is evenly coated.
- Heat 2 tbsp oil in a large frying pan over high heat. Brown the chicken in two batches so pieces get color. Remove with a slotted spoon and set aside.
- Lower the heat to low–medium. Add 2 tbsp butter to the same pan and let it melt. Add the diced onions, minced garlic, 1 tsp dried thyme and optional ½ tsp celery salt. Cook for about 5 minutes until the onions soften.
- Sprinkle 25 g (3 tbsp) flour over the onions. Stir constantly for about a minute — it will form a lumpy paste.
- Pour in a small splash of the 1 litre chicken stock and whisk to combine, breaking up lumps. Continue adding stock a little at a time while whisking until all the stock is incorporated and the sauce is smooth.
- Stir in 300 ml milk and keep stirring over the heat until the sauce thickens. Add 2 tbsp lemon juice.
- Add the sliced mushrooms and the browned chicken back to the pan. Season with 1/2 tsp salt and 1/2 tsp pepper. Cover with a lid and simmer gently on the hob for 20 minutes.
- Alternatively, transfer to a casserole dish, cover with foil and bake at 175°C/350°F (fan) for 30 minutes.
- Remove the lid and stir in 240 ml double cream. Heat through for another 5 minutes.
- If you want a thicker sauce, gradually stir in the cornflour slurry until you reach the desired consistency.
- Finish with chopped parsley and serve with mashed potatoes and your favourite vegetables.
