Creamy Chicken Mushroom Casserole: a one-dish dinner with no canned soup

This creamy chicken mushroom casserole is the dish I make when I want dinner to feel comforting but not heavy. Chicken breasts are seared, topped with soft shallots, garlic and thin-sliced shiitake mushrooms, then baked in a savory coconut cream sauce until everything is tender and the sauce turns rich and spoonable.

If you grew up on a chicken and mushroom soup casserole made with canned cream soup, this is a similar comfort with fewer ingredients you can’t pronounce. Coconut milk and chicken broth make the creamy mushroom sauce, and a little nutritional yeast adds a cheesy, savory note. It’s dairy-free, gluten-free, and simple enough that after the first time you’ll make it without looking at the recipe.

It came about by accident, when I wanted the flavor of a stroganoff-style dinner without the extra pots. Now it’s one of my go-to weeknight recipes.

Why This Creamy Chicken Mushroom Casserole Works

Searing the chicken first is the step that matters most. A quick browning in a hot skillet with ghee or butter builds the deep, roasted flavor that baking alone can’t. The chicken only needs color, not cooking through, because it finishes in the oven.

Layering the aromatics and mushrooms on top of the chicken protects the breasts from drying out and lets their juices drip into the sauce. Sautéing the garlic and shallots first mellows them into sweetness, and shiitake mushrooms bring an earthy, meaty depth that stands in for the cream-of-mushroom flavor.

Sear for flavor, bake for tenderness, and let the mushrooms flavor the sauce as it thickens.

The sauce needs no flour or cornstarch. The coconut milk is only poured up to the sides of the chicken, not over it, so the tops brown while the sauce reduces and thickens in the oven.

Tips Before You Start

Use chicken breasts of similar thickness. If one is much thicker, slice it horizontally into cutlets or pound it lightly so everything finishes at the same time.

Slice the shiitake mushrooms thinly, about ⅛ inch. Thin slices soften quickly and release their flavor into the sauce, while thick slices can stay chewy. Remove and discard the tough stems.

Quick Recipe Information

Ingredients

Chicken

• 4 boneless, skinless chicken breasts (about 1½ to 2 lb) (lean and quick-cooking; chicken thighs work too and stay juicier)
• 1 tsp salt and ½ tsp black pepper (builds the base seasoning)
• 1 tsp garlic powder, 1 tsp chili powder, 1 tsp onion powder (a savory, lightly smoky rub; skip the chili powder for a milder dish)
• ½ tsp dried thyme or oregano (optional; adds an herby note)
• 1–2 tbsp ghee or butter (high-heat searing fat; olive oil or avocado oil for dairy-free)

Mushroom layer

• 4 garlic cloves, thinly sliced (flavors the sauce without burning)
• 2 shallots, thinly sliced (sweeter and milder than onion; yellow onion is a fine swap)
• 8 oz shiitake mushrooms, stems removed and thinly sliced (meaty and savory; cremini is a good substitute)

Creamy sauce

• 1 cup full-fat coconut milk (makes the sauce creamy without dairy; heavy cream works if you eat dairy)
• ¼ cup chicken broth (thins the coconut milk; try my chicken bone broth)
• 1–2 tbsp nutritional yeast, plus extra for topping (adds a savory, cheesy flavor; parmesan is an alternative if not dairy-free)

Equipment Needed

• Large oven-safe skillet, or a skillet plus a baking dish
• 9×13-inch baking dish (if not using an oven-safe skillet)
• Sharp knife and cutting board
• Tongs
• Instant-read thermometer

Step-by-Step Instructions

1. Heat the oven. Preheat to 400°F. Pat the chicken dry with paper towels so it sears instead of steaming.
2. Season one side. Mix the salt, pepper, garlic powder, chili powder, onion powder and dried herbs. Season only the top of each breast, since the other side will be seasoned after flipping.
3. Sear. Heat the ghee in a large skillet over medium-high heat. Place the chicken seasoned-side down and sear 2–3 minutes until deeply golden. Season the top, flip, and sear 2 minutes more. The chicken should not be cooked through.
4. Transfer. Move the chicken to a baking dish, or turn off the heat if using an oven-safe skillet.
5. Cook the aromatics. In the same skillet, sauté the garlic and shallots with a pinch of salt for 1–2 minutes, until fragrant and soft. Layer them over the chicken. The browned bits in the pan add flavor.
6. Add the mushrooms. Arrange the thin-sliced shiitake over the aromatics in an even layer. They will shrink and soften as they bake.
7. Add the sauce. Stir the coconut milk and chicken broth together until smooth. Pour into the dish until the liquid reaches the sides of the chicken but doesn’t cover it. Sprinkle nutritional yeast over the top.
8. Bake. Bake uncovered for 20–25 minutes, until the chicken reaches 165°F inside and the sauce bubbles around the edges.
9. Thicken if needed. If the sauce looks thin, set the chicken aside and simmer the sauce on the stovetop for 3–5 minutes to reduce it.
10. Serve. Rest 5 minutes, sprinkle with more nutritional yeast, and spoon the creamy mushroom sauce over the top.

Chef’s Tips

• Dry the chicken well. Surface moisture prevents browning, and browning is where much of the flavor comes from.
• Stir the coconut milk first. It separates in the can, and mixing it with broth gives an even, smooth sauce.
• Don’t over-sear. The chicken finishes in the oven, so extra time in the pan leads to dry breasts.
• Salt the aromatics. A pinch draws out moisture, helping shallots and garlic soften without browning too much.
• Use a thermometer. Breasts vary in thickness, and 165°F is the point of juicy and safe.
• Rest before serving. A few minutes lets juices settle and the sauce thicken slightly.

Common Mistakes

Recipe Variations

• Vegetarian: Replace the chicken with thick cauliflower steaks or portobello caps, and use vegetable broth.
• Gluten-Free: Already gluten-free. Check the broth label.
• Spicy: Add red pepper flakes or a teaspoon of harissa to the sauce.
• Dairy-Free: This is already dairy-free with coconut milk and oil in place of ghee.
• Low Carb: The base recipe is low in carbs. Serve with cauliflower rice or zucchini noodles.
• Kid-Friendly: Skip the chili powder and slice the chicken before serving.
• Chicken Stroganoff Casserole: Stir a tablespoon of Dijon mustard and a splash of Worcestershire into the sauce, then serve over noodles.

Storage & Reheating

Refrigerator: Cool, cover, and refrigerate for up to 4 days.

Freezer: Freeze in airtight containers for up to 2 months. The sauce may separate slightly, but stirring after reheating brings it back.

Reheating: Warm covered in a 325°F oven for 15–20 minutes, or gently on the stovetop with a splash of broth. Microwave in short bursts.

Meal prep: Sear the chicken and slice the vegetables a day ahead, then assemble and bake when you’re ready.

Serving Suggestions

• Cauliflower rice or mashed potatoes: They soak up the creamy mushroom sauce.
• Sheet pan roasted vegetables: Try my sheet pan roasted vegetables for a colorful side.
• Paleo spaghetti noodles: Pair with the paleo spaghetti noodles for a stroganoff-style plate.
• A green salad or steamed broccoli: Their freshness cuts through the creamy sauce.
• Dry white wine: Its acidity balances the richness of the coconut cream.

Nutrition Information

Estimated per serving. Values are approximate and vary with ingredients and portion size.

Frequently Asked Questions

• Can I make this without coconut milk?

  Yes. Use heavy cream or half-and-half for a traditional creamy mushroom sauce casserole.

• Do I need to sear the chicken first?

  It’s optional, but searing adds flavor and color that baking alone won’t.

• What mushrooms can I use?

  Shiitake gives the deepest flavor, but cremini, white button, or a mix work well.

• Can I use chicken thighs?

  Yes. Bake them a bit longer, until they reach 175°F.

• Why is my sauce thin?

  Too much liquid or mushrooms releasing water. Simmer the sauce on the stovetop for a few minutes to thicken it.

• What is nutritional yeast?

  It is a deactivated yeast with a savory, cheesy flavor. Parmesan is a substitute if dairy isn’t a concern.

• Can I prepare it ahead?

  Yes. Sear and assemble up to a day ahead, refrigerate, and bake for a few extra minutes.

• Can I freeze the casserole?

  Yes, for up to 2 months. Reheat gently and stir the sauce.

• Is it healthy?

  It’s high in protein and made from whole ingredients, with no canned soup or refined thickeners.

• How do I know the chicken is done?

  The thickest part should read 165°F on an instant-read thermometer, and the juices should run clear.

Conclusion

This creamy chicken mushroom casserole shows how little you need for a comforting dinner: a quick sear, a layer of mushrooms, and a creamy sauce. It’s dairy-free, easy to adapt, and hard to overcook if you watch the thermometer.

Save it for a busy weeknight, and if you’d like to see the technique, the video below walks through it.