This post may contain affiliate links. Please read our disclosure policy.
This single serving mushroom casserole is made with a rich, from-scratch cream sauce and rice that soaks up every bit of flavor. No canned soup, just real ingredients and one small baking dish.
Featured Comment
“Absolutely wonderful. Highly recommend it.”
– dragnlaw
Quick Look
- Prep Time: 10 minutes
- Cook Time: 40 minutes
- Total Time: 50 minutes
- Equipment: 10-inch skillet and a 4×6-inch or 5×5-inch baking dish
- Cook Method: Stovetop + Oven
- Servings: 1
- Difficulty: Easy
- Flavor Profile: Earthy mushrooms in a garlicky cream sauce with tender rice and a touch of rosemary.
A simple baked mushroom casserole with rice and a from-scratch sour cream sauce, sized for one and ready in under an hour.
Why I Love This Small Mushroom Casserole Recipe
Most mushroom casserole recipes start with a can of cream of mushroom soup and serve a crowd. This one starts with a skillet, fresh mushrooms, and a cream sauce you make yourself. It takes a few extra minutes, but the difference is obvious the first time you taste it.
I make this when I want a real dinner without a lot of effort. You sauté the mushrooms and onions in a skillet, stir together a quick cream sauce with sour cream and a little rosemary, pour it all into a small baking dish, and let the oven do the rest. The rice cooks right in the sauce, so by the time it comes out, every grain has absorbed all that garlicky, savory flavor.
This small mushroom casserole uses 4 ounces of mushrooms (about 1 cup sliced) and ¼ cup of rice for a generous single serving. I adjusted the broth and cream amounts a few times to get the liquid right. Too little and the rice dries out, too much and it turns soupy. This version bakes covered for 40 minutes and comes out with the rice fully tender and just enough sauce clinging to everything.
I’ve been developing single serving and small batch recipes for over a decade, and this one stays in regular rotation. If you like mushroom-based dishes, try my mushroom pasta for one, crustless spinach and mushroom quiche, or single serving beef stroganoff.
Ingredient Notes
This easy mushroom casserole recipe uses simple, everyday ingredients to build a from-scratch cream sauce that bakes with the rice. If you have leftover ingredients, check out our Leftover Ingredients Recipe Finder.
Mushrooms: Cremini (baby bella) or white button mushrooms both work well here. Cremini have a slightly deeper, earthier flavor, but white button are just as good and usually cheaper. Rinse briefly in a colander and pat dry; don’t soak them or they won’t brown.
Use leftover mushrooms in chicken marsala for one or single serving mushroom risotto.
Onion and garlic: The base of the sauce. The onion cooks until translucent, then the garlic gets about 30 seconds so it doesn’t burn. Together they give the cream sauce most of its savory depth.
Chicken broth: Use low sodium so you can control the salt. The broth simmers with the mushrooms and becomes part of the liquid that cooks the rice. Swap in vegetable broth for a vegetarian version.
Use leftover broth in our single serving soup recipes, chicken and dumplings for one or a cheesy broccoli casserole for one.
Sour cream and heavy cream: These two make the sauce. Sour cream adds tang and body, heavy cream smooths it out and gives the sauce enough liquid to cook the rice through. Greek yogurt can replace the sour cream. Whole milk or half-and-half can replace the heavy cream, but the sauce will be thinner.
Use leftover sour cream and heavy cream in small batch chicken and biscuits casserole, chicken tetrazzini for one, or a single serve cauliflower casserole.
Rice: Medium or long-grain white rice works best. Basmati is fine too. The rice goes in uncooked and absorbs the sauce as it bakes, so don’t use instant or quick-cooking varieties; they’ll turn to mush.
Use leftover rice in rice pudding for one.
Recipe Variations
Use these simple swaps to change up this mushroom and onion casserole recipe.
Cheesy mushroom casserole. Stir in 2 tablespoons of shredded Gruyère, cheddar, or Parmesan before baking.
Crispy breadcrumb topping. Mix ¼ cup of homemade breadcrumbs or crushed Ritz crackers with 1 tablespoon of butter, melted. After baking, remove the foil, sprinkle the mixture over the top, and bake uncovered for 5 more minutes.
Add a vegetable. Stir ¼ cup of steamed or blanched chopped broccoli into the baking dish before adding the cream mixture.
Add protein. Mix in ¼ cup of cooked chicken, turkey, or tofu to make it heartier.
Dairy-free option. Use coconut cream in place of heavy cream, a plant-based sour cream, and vegetable broth instead of chicken broth.
How To Make A Mushroom Casserole For One
These photos and step-by-step instructions show you how to make this simple mushroom casserole recipe. See the recipe card below for exact ingredient amounts.
- Preheat the oven to 375°F (190°C).
- Heat 1 tablespoon of olive oil in a 10-inch skillet over medium heat. Add the onions and cook for about 2 minutes, stirring frequently, until translucent. Add the garlic and cook for 30 seconds.
- Increase the heat to medium-high and add the remaining ½ tablespoon of olive oil. Add the mushrooms, ¼ teaspoon of salt, and pepper. Cook for 5 to 7 minutes, stirring occasionally, until the mushrooms have released their liquid and started to brown.
- Pour in the chicken broth and bring to a simmer.
- Remove the skillet from the heat and stir in the heavy cream, sour cream, remaining ¼ teaspoon of salt, and dried rosemary until smooth.
- Add the uncooked rice to 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 aluminum foil and bake for 40 minutes. Remove the foil and check for excess liquid. If the casserole looks watery, bake uncovered for a few more minutes until the liquid has absorbed. Serve hot.
Expert Tips
Don’t skip the browning step. Cooking the mushrooms for a full 5 to 7 minutes lets them release their moisture and develop flavor. If you crowd them or pull them too early, the sauce will taste watery.
Use regular white rice, not instant. Instant or quick-cooking rice absorbs liquid too fast and turns to mush. Medium or long-grain white rice holds its shape and cooks evenly in the 40-minute bake time.
Cover the dish tightly. The foil traps steam, which is what cooks the rice. If it’s loose, the liquid evaporates before the rice is done and you’ll end up with crunchy, undercooked grains.
Place the baking dish on a sheet pan. The sauce can bubble over as the rice absorbs it. A rimmed baking sheet underneath saves you from cleaning the oven.
Let it rest for a few minutes before serving. The sauce thickens slightly as it sits, and the rice finishes absorbing the last bit of liquid.
Troubleshooting
If your mushroom casserole isn’t turning out quite right, here is how to fix common issues like watery sauce, undercooked rice, or bland flavor.
Why is my mushroom casserole watery?
The mushrooms weren’t browned long enough before baking. Mushrooms hold a lot of water, and if they don’t cook for the full 5 to 7 minutes in the skillet, that moisture releases into the sauce during baking. Remove the foil and bake uncovered for 3 to 5 more minutes until the excess liquid absorbs.
Why is the rice still hard after baking?
The rice needs more time, liquid, or trapped steam to cook through. Add a splash of broth, re-cover tightly with fresh foil, and bake for another 5 minutes. If this happens often, check that your foil is sealed well and that your oven is running at the correct temperature. An oven thermometer is the easiest way to check.
Why does my mushroom casserole taste bland?
Low sodium broth varies by brand, so the recipe may need more salt than expected. Stir in a pinch of salt and taste again. A small squeeze of lemon juice can also brighten the overall flavor without changing the taste of the dish.
Why are the mushrooms pale and soggy?
They went into the oven without browning first. Cook the mushrooms on medium-high heat for the full 5 to 7 minutes, and let them sit between stirs so they brown rather than steam. Pale mushrooms release water into the sauce and dilute the flavor.
Why is the rice mushy?
Too much liquid or the wrong type of rice will cause this. Make sure you’re using regular long-grain white rice and measuring the broth and cream accurately. Instant or quick-cooking rice breaks down too fast and can’t hold its shape during a 40-minute bake.
Serving Suggestions
This mushroom casserole with rice is a filling main course on its own, but it also pairs well as a side dish.
Frequently Asked Questions
Fresh mushrooms, sour cream, heavy cream, and low sodium chicken broth. The sauce is made from scratch on the stovetop in about 10 minutes. There is no canned cream of mushroom soup in this recipe.
Store it in an airtight container in the refrigerator for up to 3 days. Reheat in the microwave or in the oven at 350°F until warmed through. Add a splash of broth when reheating to loosen the rice.
Yes. Double all the ingredients and use two 5×5-inch baking dishes or one 6×8-inch dish. Keep the bake time at 40 minutes and check for doneness the same way.
Medium or long-grain white rice works best. Basmati is also fine. Do not use instant, quick-cooking, or brown rice. Instant rice turns mushy, and brown rice needs more liquid and a longer bake time than this recipe allows.
Yes, but keep the sauce and rice separate. Make the mushroom sauce on the stovetop, let it cool, and refrigerate in an airtight container for up to 24 hours. When ready to bake, pour the sauce over the uncooked rice in the baking dish and bake as directed.
No. The cream sauce and rice both change texture when frozen and thawed. This recipe is best made fresh or stored in the refrigerator for up to 3 days.
Ways To Use Leftover Ingredients
If you have any ingredients leftover from this recipe, check out our Leftover Ingredients Recipe Finder or you might like to consider using them in any of these single serving and small batch recipes:
If you’ve tried this mushroom casserole for one recipe or any recipe on One Dish Kitchen please let me know how you liked it by rating the recipe and telling me about it in the comment section below.
If you take a picture please tag us on Instagram (@onedishkitchen) we’d love to see it!
Mushroom Casserole For One
Equipment
- 5-inch baking dish or use a 4×6-inch baking dish
Ingredients
- 1 ½ tablespoons olive oil – divided
- ¼ cup chopped onions
- 1 clove garlic – minced
- 4 ounces sliced mushrooms (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).
- Heat 1 tablespoon of olive oil in a 10-inch skillet over medium heat.
- Add the chopped onions and cook for about 2 minutes, stirring frequently, until translucent.
- Add the minced garlic and cook for 30 seconds, stirring constantly.
- Increase the heat to medium-high and add the remaining ½ tablespoon of olive oil.
- Add the sliced mushrooms, ¼ teaspoon of salt, and pepper. Cook for 5 to 7 minutes, stirring occasionally, until the mushrooms have released their liquid and started to brown.
- Pour in the chicken broth and bring to a simmer.
- Remove the skillet from the heat and stir in the heavy cream, sour cream, remaining ¼ teaspoon of salt, and dried rosemary until smooth.
- Add the uncooked rice to 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 the dish tightly with aluminum foil and bake for 40 minutes.
- Remove the foil and serve hot.
Notes
Nutrition
The information shown is an estimate provided by an online nutrition calculator. It should not be considered a substitute for a professional nutritionist’s advice.
Picked up some mixed mushrooms on sale, so I had to try this recipe. I also had farro so I used that instead of rice. The seasoning was spot on. Will be making again.
I’m so happy you enjoyed it!