This creamy Chicken Mushroom Casserole is a delicious dinner that is easy to prepare using chicken breasts, mushrooms, garlic, heavy cream, and onions.

To make Chicken Mushroom Casserole in your slow cooker or crockpot, just toss all your ingredients in, set it to low, and let it cook for 6 hours. It’s that easy, no fuss needed!

Give this a go and don’t be shy to drop a comment below! Trust me, it’s so good it might just become your new go-to dinner.

Jump to Recipe Print Recipe

Slow Cooker Chicken Mushroom Casserole Ingredients

• 1 kg (2.2 lb) of chicken breasts
• 1 onion, finely chopped
• 2 tsp of minced garlic
• 250 g (8.8 oz) of sliced mushrooms
• 2 tsp of Dijon mustard
• 1 tsp of fresh oregano, finely chopped
• 250 ml (8.5 fl oz) of chicken stock
• 125 ml (4.2 fl oz) of heavy cream
• 250 g (8 oz) of cream cheese

How To Make Slow Cooker Chicken Mushroom Casserole

1. Load Your Slow Cooker: Start by chucking the chopped onion, minced garlic, and sliced mushrooms into your slow cooker. Add the Dijon mustard and chopped oregano, then drown them all in chicken stock to kick off the flavor party.
2. Add the Chicken: Plop the chicken breasts right on top, making sure they get a nice bath in the flavorful mix.
3. Set to Cook: Flip the switch to low and let it slow cook for 6 hours. This is your cue to kick back or get busy with something else—let the cooker do its thing.
4. Boost the Creaminess: Once the time’s up, fish out the chicken breasts and stir in the heavy cream and cream cheese. Mix until the cream cheese is melted and the sauce looks silky and inviting.
5. Thicken the Sauce: Return the chicken to the slow cooker, crank it up to high, and let it bubble away for another 30 minutes or until the sauce thickens to a luscious texture.
6. Season to Taste: Sneak a taste and slap in some salt and pepper to get it just right.
7. Serve and Enjoy: Scoop it onto plates, maybe over some fluffy rice or next to a pile of buttery mashed potatoes, and dig in.

Can I Take off the Cream Cheese?

Yes, if you prefer to leave out the cream cheese, consider adding an additional 60 ml (about 1/4 cup) of heavy cream to maintain the sauce’s creamy texture.

What Can I Use Instead of Dijon Mustard in This Recipe?

If you don’t have Dijon mustard, you can use an equal amount of yellow mustard or whole grain mustard. So, if the recipe calls for 2 teaspoons of Dijon, use 2 teaspoons of your substitute.

Recipe Tips

• Boosting Flavor: Add a splash of white wine to the base before cooking to deepen the flavors and give a slight tang that complements the creamy texture of the casserole.
• Thicken It Up: If you’re looking for a thicker sauce without cornstarch, let the casserole cook uncovered on high for the last 20 minutes to reduce the liquid.
• Layering Ingredients: Always layer your veggies under the chicken in the slow cooker to ensure they soak up all the juices and flavors during the long cooking process.
• Spice It Right: Don’t be shy with spices; a pinch of smoked paprika or a dash of cayenne can turn this dish from simple to simply amazing with very little effort.

Recipe Variations

• Go Green: Toss in some spinach or kale during the last 30 minutes of cooking for a pop of color and a nutritional boost—just enough time to wilt but not lose texture.
• Switch the Protein: Not a fan of chicken? Substitute it with turkey breasts or even pork tenderloin for a delightful twist on the classic chicken mushroom flavor profile.
• Dairy Alternatives: For a dairy-free version, use coconut cream instead of heavy cream and skip the cream cheese; you’ll get a lovely, creamy texture with a hint of coconut.
• Mushroom Variety: Mix it up with a variety of mushrooms like shiitake, portobello, or cremini to elevate the earthy flavors and bring a gourmet touch to this homely dish.

What To Serve With Chicken Mushroom Casserole

Serve your Chicken Mushroom Casserole with a side of roasted garlic cauliflower, Green Beans With Smoked Turkey, or some crispy smashed potatoes.

You can also pair it with grilled asparagus, Orange-cardamom Slow Cooker Carrots, or a fresh fennel slaw for a crunchy contrast to the creamy casserole.

How To Store Leftover Chicken Mushroom Casserole

In The Fridge:

To store leftover Chicken Mushroom Casserole in the fridge, transfer it to an airtight container. Ensure it cools to room temperature before sealing and placing it in the fridge. Properly stored, it will keep for up to 4 days.

In The Freezer:

First, allow it to cool completely. Then, portion the casserole into airtight containers or freezer-safe bags. Label each with the date, and it will keep well for up to 3 months. Thaw in the fridge overnight when ready to use.

How To Reheat Leftover Chicken Mushroom Casserole

Reheat your leftover Chicken Mushroom Casserole by placing it in a microwave-safe dish and covering it lightly. Microwave on high for 3-4 minutes, stirring halfway through to ensure even heating.

Check out More Slow Cooker Recipes:

• Slow Cooker Sausage and Baked Bean Casserole
• Beef and Ale Slow Cooker Casserole
• Slow Cooker Broccoli Rice and Cheese Casserole