Creamy mushroom casserole for one with garlic, onions, and rosemary. This easy single-serving recipe combines sautéed mushrooms, heavy cream, sour cream, and long-grain rice for a hearty, comforting meal. Perfect for quick dinners, cozy lunches, or healthy homemade meals, this casserole is simple to prepare and full of flavor.

Ingredients

1 ½ tablespoons olive oil, divided
¼ cup chopped onions
1 clove garlic, minced
4 ounces sliced mushrooms (about 1 cup)
½ teaspoon kosher salt, divided
⅛ teaspoon black pepper
⅓ cup low-sodium chicken broth
3 tablespoons heavy cream
2 tablespoons sour cream
¼ teaspoon dried rosemary
¼ cup long-grain white rice

Instructions

Preheat the oven to 375°F (190°C).
In a medium skillet, heat 1 tablespoon olive oil over medium heat. Add the onions and cook for 2 minutes, stirring frequently, until translucent. Add the garlic and cook for 30 seconds until fragrant.
Increase heat to medium-high and add ½ tablespoon olive oil. Add the mushrooms, ¼ teaspoon salt, and black pepper. Cook for 5–7 minutes, stirring occasionally, until the mushrooms are browned.
Pour in the chicken broth and bring to a simmer.
Remove from heat and stir in the heavy cream, sour cream, remaining ¼ teaspoon salt, and dried rosemary until combined.
Place the uncooked rice in a 4×6-inch or 5×5-inch baking dish.
Pour the mushroom sauce over the rice and stir gently to combine. Place the baking dish on a rimmed baking sheet to catch any spills.
Cover tightly with foil and bake for 40 minutes, or until the rice is tender and the casserole is heated through. Serve hot.

Why You’ll Love This Recipe

This mushroom casserole is creamy, flavorful, and perfectly portioned for one. The combination of sautéed mushrooms, garlic, and rosemary with a creamy sauce makes it a comforting meal that’s simple to prepare without wasting leftovers.

Tips

Use a rimmed baking sheet to prevent spills when baking.
Cover tightly with foil to ensure the rice cooks evenly and absorbs all the flavors.
For extra richness, stir in a small amount of grated Parmesan before baking.

Variations and Substitutions

Substitute white rice with brown rice or quinoa for a healthier option, adjusting cooking time accordingly.
Use vegetable broth instead of chicken broth for a vegetarian version.
Swap mushrooms for a mix of vegetables like zucchini, bell peppers, or spinach.
Replace sour cream with Greek yogurt for a lighter version.

FAQs

Q: Can I make this casserole ahead of time?
A: Yes! Assemble the casserole up to step 7, cover, and refrigerate for up to 24 hours. Bake as directed when ready to eat.

Q: Can I freeze leftovers?
A: Yes, allow the casserole to cool completely, then freeze in an airtight container for up to 1 month. Reheat in the oven covered with foil.

Q: Can I make this recipe for more servings?
A: Absolutely! Multiply all ingredients by the number of servings and use a larger baking dish. Adjust baking time as needed.

Serving

Serve this mushroom casserole on its own for a cozy, filling meal, or pair it with a side salad or roasted vegetables for a complete dinner.

Suggestions

Garnish with fresh parsley or chives for color and added flavor.
Add a sprinkle of shredded cheese on top before baking for a cheesy twist.
Serve with crusty bread to soak up the creamy sauce.