If you are looking for a warm, comforting side dish or vegetarian-friendly dinner, this Creamy Mushroom and Rice Casserole is a delicious recipe to keep in your collection. Tender rice is combined with golden sautéed mushrooms, garlic, onions, herbs, cream, and plenty of melted cheese, then baked until hot, bubbling, and lightly golden on top.
The mushrooms give this casserole a deep savory flavor, while the creamy sauce keeps the rice soft and rich. Parmesan adds a nutty finish, mozzarella brings plenty of melt, and thyme pairs naturally with the earthy mushrooms.
This recipe works beautifully for family dinners, holiday gatherings, potlucks, or meal prep. Serve it on its own with a fresh salad, or use it as a side dish with roasted chicken, steak, salmon, pork chops, or grilled vegetables.
Why You’ll Love This Creamy Mushroom and Rice Casserole
One of the best things about this casserole is its rich texture. The rice absorbs the creamy mushroom sauce as it bakes, creating a soft, comforting center while the cheese on top becomes bubbly and golden.
The mushrooms are cooked separately before being added to the casserole. This is important because properly browning them develops much more flavor than adding raw mushrooms directly to the rice.
This recipe is also easy to customize. You can add spinach, broccoli, peas, chicken, bacon, or different cheeses depending on what you have available.
It is also an excellent make-ahead recipe because the casserole can be assembled earlier in the day and baked shortly before serving.
Ingredients
For the Mushroom Mixture
- 16 ounces cremini or button mushrooms, sliced
- 2 tablespoons olive oil
- 2 tablespoons unsalted butter
- 1 medium yellow onion, finely diced
- 4 garlic cloves, finely minced
- 1 teaspoon dried thyme
- ½ teaspoon dried oregano
- ¾ teaspoon salt
- ½ teaspoon freshly ground black pepper
For the Creamy Sauce
- 2 tablespoons unsalted butter
- 2 tablespoons all-purpose flour
- 1½ cups vegetable or chicken broth
- 1 cup whole milk
- ½ cup heavy cream
- 4 ounces cream cheese, softened
- ½ teaspoon garlic powder
- ½ teaspoon onion powder
- ¼ teaspoon paprika
For the Casserole
- 4 cups cooked long-grain white rice
- 1 cup shredded mozzarella cheese
- 1 cup shredded sharp cheddar cheese
- ½ cup freshly grated Parmesan cheese
- 2 tablespoons chopped fresh parsley
For the Topping
- ½ cup shredded mozzarella
- ¼ cup grated Parmesan
- ½ cup panko breadcrumbs, optional
- 2 tablespoons melted butter, optional
- Fresh parsley for garnish
How to Make Creamy Mushroom and Rice Casserole
1. Preheat the Oven
Preheat your oven to 375°F (190°C).
Lightly grease a 9-by-13-inch baking dish with butter or nonstick cooking spray.
Set it aside while you prepare the mushrooms and sauce.
2. Prepare the Mushrooms
Wipe the mushrooms clean and slice them evenly.
Try not to soak mushrooms in water because they absorb moisture easily, which can make browning more difficult.
Heat olive oil and 1 tablespoon butter in a large skillet over medium-high heat.
Add the mushrooms in a single layer.
If your skillet is not large enough, cook them in two batches.
3. Brown the Mushrooms
Let the mushrooms cook undisturbed for approximately 3–4 minutes before stirring.
Once the first side becomes golden, stir and continue cooking for another 4–5 minutes.
The mushrooms should shrink slightly and develop deep golden edges.
Proper browning is one of the most important steps in this recipe because it creates a richer, more savory casserole.
4. Add Onion and Garlic
Reduce the heat to medium.
Add the remaining tablespoon of butter and the diced onion.
Cook for approximately 4 minutes, stirring occasionally, until softened.
Add the minced garlic, thyme, oregano, salt, and black pepper.
Cook for another 30–45 seconds, until fragrant.
Transfer the mushroom mixture to a bowl and set aside.
5. Start the Creamy Sauce
In the same skillet, melt 2 tablespoons butter over medium heat.
Sprinkle in the flour.
Whisk continuously for about 1 minute.
This creates a simple roux that will help thicken the sauce.
Slowly pour in the broth while whisking to prevent lumps.
6. Add the Milk and Cream
Pour in the whole milk and heavy cream.
Continue stirring until smooth.
Add garlic powder, onion powder, and paprika.
Bring the mixture to a gentle simmer.
Cook for approximately 2–3 minutes, stirring frequently, until the sauce starts to thicken.
It should coat the back of a spoon but remain pourable.
7. Add the Cream Cheese
Reduce the heat to medium-low.
Add the softened cream cheese.
Whisk until completely melted and incorporated into the sauce.
The cream cheese makes the casserole especially smooth and creamy.
Taste the sauce and adjust the salt and black pepper if needed.
8. Add the Cheese
Stir in the mozzarella, cheddar, and Parmesan.
Keep the heat low and stir until the cheese has melted.
Do not allow the sauce to boil aggressively after adding the cheese because high heat can make cheese sauces grainy.
9. Combine the Rice and Mushrooms
Place the cooked rice in a large mixing bowl.
Add the browned mushrooms and onion mixture.
Pour the creamy cheese sauce over the rice.
Add the chopped fresh parsley.
Fold everything together gently until the rice is evenly coated.
The mixture should look creamy before baking. If it seems too thick, stir in a small splash of broth or milk.
10. Transfer to the Baking Dish
Spoon the rice mixture into the prepared baking dish.
Spread it into an even layer.
Avoid pressing it down too firmly. Keeping the mixture slightly loose helps the casserole stay creamy.
11. Add the Topping
Sprinkle mozzarella and Parmesan evenly over the casserole.
For a crispy finish, combine the panko breadcrumbs with melted butter and scatter them over the cheese.
The breadcrumb topping is optional, but it creates a nice contrast to the creamy rice underneath.
12. Bake Until Golden
Bake uncovered for approximately 20–25 minutes.
The casserole should be hot throughout and bubbling around the edges.
The cheese should be completely melted.
For additional color, broil for the final 1–2 minutes, watching carefully.
13. Let the Casserole Rest
Remove the casserole from the oven.
Allow it to rest for approximately 5–10 minutes.
This short resting time allows the creamy sauce to settle and makes the casserole easier to serve.
Sprinkle with fresh parsley before bringing it to the table.
What to Serve With Creamy Mushroom and Rice Casserole
This casserole can be served as a vegetarian main dish with a fresh salad and roasted vegetables.
It also makes an excellent side for garlic herb chicken, baked chicken breasts, grilled steak, pork chops, or roasted turkey.
For seafood, try serving it alongside salmon, shrimp, or baked cod.
Roasted asparagus, broccoli, green beans, Brussels sprouts, or carrots can add freshness and color to the plate.
Warm dinner rolls or garlic bread are another delicious addition for a comforting family meal.
Tips for the Best Mushroom and Rice Casserole
Brown the mushrooms properly. Golden mushrooms have significantly more flavor than pale steamed mushrooms.
Do not overcrowd the skillet. Crowding traps steam and prevents browning.
Use cooked rice. This recipe is designed for already cooked rice, which makes the final texture easier to control.
Keep the sauce slightly loose. The rice will continue absorbing moisture as it bakes.
Use freshly shredded cheese when possible. It generally melts more smoothly.
Taste before adding extra salt. Broth, Parmesan, and cheddar already contribute saltiness.
Let the casserole rest. This helps the sauce thicken without becoming dry.
Easy Recipe Variations
Creamy Chicken Mushroom Rice Casserole
Add 2–3 cups shredded cooked chicken before transferring the mixture to the baking dish.
Spinach Mushroom Rice Casserole
Stir 2 cups fresh spinach into the mushroom mixture and cook until just wilted.
Broccoli Mushroom Rice Bake
Add 2 cups lightly steamed broccoli florets to the rice mixture.
Bacon Mushroom Rice Casserole
Add ½ cup crispy crumbled bacon and sprinkle extra bacon over the top before serving.
Garlic Parmesan Mushroom Rice
Increase the Parmesan and add an extra garlic clove for a stronger garlic-cheese flavor.
Wild Rice Mushroom Casserole
Replace some or all of the white rice with cooked wild rice for a nuttier texture and flavor.
Storage and Reheating
Allow leftover casserole to cool before transferring it to an airtight container.
Refrigerate for up to 3–4 days.
To reheat an individual serving, add a teaspoon of milk or broth and microwave until hot.
For larger portions, cover with foil and reheat in a 350°F (175°C) oven for approximately 15–20 minutes.
Adding a small amount of liquid before reheating helps restore the creamy texture.
Make-Ahead Instructions
This casserole can be assembled up to 24 hours ahead.
Prepare the rice, mushroom mixture, and creamy sauce.
Combine everything in the baking dish, cover tightly, and refrigerate.
If using breadcrumbs, wait to add them until just before baking so they remain crisp.
Bake directly from the refrigerator, adding approximately 5–10 extra minutes if needed.
Final Thoughts
This Creamy Mushroom and Rice Casserole is an easy comfort-food recipe packed with golden mushrooms, tender rice, garlic, herbs, rich cream sauce, and plenty of melted cheese.
The key to the best flavor is browning the mushrooms thoroughly before building the casserole. That simple step gives the entire dish a deeper, more savory character. Keeping the sauce slightly loose before baking also ensures the rice stays creamy rather than dry.
Serve it as a satisfying vegetarian dinner, pair it with chicken or steak for a hearty meal, or bring it to a holiday gathering as a comforting side dish. With its creamy center, golden cheese topping, and rich mushroom flavor, this casserole is a versatile recipe that works beautifully for almost any occasion.