Why You’ll Love Creamy Chicken and Mushroom One‑Pan CasseroleRecipe

It’s a big‑batch recipe: easily serves around 10, so ideal for families or leftovers.
Versatile cooking: you can make it on the stovetop in a large frying pan or transfer it into the oven as a traditional casserole.
Freezer‑friendly: make ahead, freeze half for another night, then simply reheat when ready.
Plenty of indulgent sauce that’s perfect for drizzling over mash or steamed veggies—everything gets nourished by the creamy goodness.
Comfort food at its finest: mushrooms, cream, chicken—all in one dish that feels like a hug on a chilly evening.

Ingredients

(Tip: You’ll find the full list of ingredients and measurements in the recipe card below.)
Chicken:
• Chicken breasts chopped into large chunks or strips
• Plain (all‑purpose) flour
• Salt
• Black pepper

Sauce:
• Oil
• Unsalted butter
• Onions, finely diced
• Garlic, minced
• Dried thyme
• Celery salt (optional)
• Plain (all‑purpose) flour
• Chicken stock
• Milk (whole or half‑fat)
• Lemon juice (approx. 1 lemon)
• Chestnut mushrooms, thickly sliced
• Salt & pepper
• Double (heavy) cream
• Cornflour (cornstarch) mixed with cold water – optional for thicker sauce
• Chopped parsley

To serve with:
• Mashed potatoes
• Sprouts
• Peas
• Sweetcorn

Directions

Place the chopped chicken in a bowl and toss with flour, salt and pepper to coat.
Heat oil in a large frying pan over high heat. In two batches, add the chicken and brown all over (it need not be cooked through at this point). Remove and set aside.
In the same pan melt the butter over low‑medium heat. Add the onions, garlic, thyme and celery salt (if using). Cook for about 5 minutes until the onions soften. Sprinkle over the flour and stir for about a minute (it will look a little lumpy).
Add a splash of the chicken stock, whisk to combine, then gradually add the rest of the stock while stirring until you have a smooth sauce with softened onions.
Add milk and keep stirring until the sauce thickens, then stir in the lemon juice.
Add the mushrooms, the cooked chicken pieces, and season with salt and pepper. Place a lid on the pan and either simmer gently on the hob for 20 minutes, or transfer to a casserole dish, cover with foil and place in an oven at 175 °C (350 °F fan) for around 30 minutes.
Remove the lid (or foil) and stir in the heavy cream. Heat through for a further 5 minutes (or return to the oven for 5 minutes if baking). If you’d like a thicker sauce, stir in the cornflour slurry little by little until desired consistency is reached.
Sprinkle chopped parsley over the top and serve with mashed potatoes, sprouted greens, peas and sweetcorn as preferred.

Servings and timing

Serves: ~10 servings.
Total time: About 1 hour 5 minutes (Prep ~15 minutes, Cook ~50 minutes).
If using the oven method: 15 minutes preparation, 30 minutes oven time, plus 5 minutes finishing with cream.

Variations

Replace mushrooms with a mix of your favourite fungi (e.g., portobello, shiitake) for extra depth of flavour.
Swap heavy cream for crème fraîche or a lighter cream version to adjust richness.
Add some chopped cooked bacon or pancetta when sautéing onions for a smoky element.
For a veggie‑forward version: omit the chicken and increase mushrooms, maybe add cubed root vegetables (parsnip, carrot) or chickpeas.
Stir in some cooked pasta or rice at the end to turn it into a creamy pasta bake.
Use a gluten‑free flour and cornflour instead of plain flour to make it gluten‑free.

Storage/Reheating

Refrigerator: After cooking, allow the casserole to cool, cover and store in the fridge for up to 1 day. Reheat in the oven at ~175 °C (350 °F) for 20‑25 minutes, or on the stovetop over medium heat for 10‑15 minutes until thoroughly heated. If sauce has thickened too much, add a splash of milk or cream to loosen.
Freezer: Cool completely, then cover and freeze. To reheat: defrost thoroughly in the fridge, then heat as above (oven ~20‑25 minutes or stovetop ~10‑15 minutes). Add a splash of cream or milk if needed.
Tip: If you halved the recipe and you find the sauce thickens more, loosen with a little extra milk when reheating.

FAQs

How do I prevent the chicken from drying out?

Make sure to brown the chicken quickly at high heat then simmer gently rather than over‑cooking. Also, covering the pan or using the oven method helps retain moisture.

Can I use chicken thighs instead of chicken breasts?

Yes — chicken thighs work well and stay moist. Adjust the browning time if they’re larger and ensure they’re cooked through during the simmer.

Can I make this ahead of time?

Absolutely. You can assemble the dish, then refrigerate it and reheat later in the oven or stovetop. The flavours will meld further.

Is it possible to make this gluten‑free?

Yes — substitute the plain flour with a gluten‑free flour blend and use cornflour for thickening instead of wheat flour.

What can I serve it with besides mashed potatoes?

It also goes well with rice, egg noodles, steamed vegetables, or even crusty bread to soak up the sauce.

Can the sauce be made dairy‑free?

Yes — use a dairy‑free cream (like coconut cream or cashew cream) and a suitable milk alternative. Be aware the flavour and texture will vary slightly.

How thick should the sauce be?

It should coat the back of a spoon and flow slowly, but not be watery. If too thin, add cornflour slurry a bit at a time until desired thickness; if too thick, loosen with milk.

How long will leftovers keep?

In the fridge: about 1 day. In the freezer: for up to 2–3 months if stored properly in a freezer‑safe container.

Can I double or halve the recipe easily?

Yes — you can halve the quantities without changing cooking times. Doubling is possible provided you use a sufficiently large pan or oven dish and ensure the chicken remains covered during cooking.

Could I cook it entirely in the oven from the start?

Yes — after browning the chicken and sautéing the onions/mushrooms on the stove, you can transfer to a casserole dish, add sauce and cream, cover and bake at 175 °C (350 °F) for about 30–35 minutes, then remove cover and bake a further 5 minutes after adding cream.

Conclusion

This creamy chicken and mushroom one‑pan casserole is the kind of hearty, comforting dish that works beautifully for family dinners, meal prep and freezing for later. With its rich sauce, generous portions and flexible cooking methods, it’s a go‑to recipe when you want something satisfying yet straightforward. Whether you serve it with mash, veggies or rice, it’s sure to hit that spot. Enjoy!

Best Creamy Chicken and Mushroom One‑Pan Casserole