4.99 from 60 ratings

This is my absolute favorite rice dish, and one of the easiest casseroles to make! All the ingredients to into a baking dish (my favorite Staub, always!) and bake to a perfectly light, fluffy, baked mushroom rice casserole with onions that caramelize themselves in the broth and seasonings. YUM.

top view of a black pan with baked rice topped with mushrooms and onions.

Hey, gluten free Thanksgiving side dish!

First, though, thank you for all the sweet words about Will! At 3 days postpartum I am totally healed and acclimated to having two children, and everyone is sleeping wonderfully, and the time change was obviously no issue for anyone.

HAHAHAHAHA no what I meant to say was we need a lot of carbs to get through this. So let's start here! This is my version of Mushroom Rice Casserole, an old side dish with consome and beefy flavors and is just SO yummy.

(it's also called stick of butter rice if that tells you anything - YUM)

In this version we definitely have some butter and beef flavor but we also have tons of extra flavor from mushrooms - I went for the blends that aren't a million dollars but ARE a step up from regular white mushrooms.

The onions and mushrooms get roasted on top of the rice, everything bakes together in the oven (so no simmering!), and this works PERFECTLY made in advance for Thanksgiving or another holiday party.

Other Delicious Starchy Side Dish Ideas

Baked Rice Ingredients

ingredients for stick of butter rice with mushrooms on a dark wood surface.

You need! Rice, butter, rosemary, oregano, beef broth, an onion, and whatever mushrooms you like. Definitely some salt, and probably more than you think since rice absorbs a lot of salt as it cooks. We want flavor!

Step By Step Instructions

Start by adding the rice, broth, and oregano and rosemary to a big baking dish or skillet with a lid - something that can go in the oven. Preheat the oven to 375F.

uncooked broth and sliced onions in a large skillet.

Slice the entire onion thinly, then stir half of the onion slices into the raw rice mixture. Cube half of the butter and toss THAT into the skillet.

It looks weird at this point. Yes. It's still correct.

Now, cover the rice (my skillet, this Staub has a lid, but tin foil works ass well!) and bake it for 30 minutes at 375F while you prepare the mushrooms. Melt the rest of the butter in a little bowl, then stir in the mushrooms and the rest of the onion slices with good sprinkles of salt and pepper.

uncooked mushrooms over rice in a large baking dish.

After 30 minutes, take the rice casserole out of the oven, uncover it and stir it, then smooth it out into one layer. Scatter the mushroom mixture over the top along with any butter from the bowl. The rice will be soupy and uncooked at this point, but you can DEFINITELY taste it and add some pinches of salt if it seems bland. Do that!

top view of stick of butter rice with onions and mushrooms.

Put the rice back in the oven UNCOVERED, and bake it for 30 minutes more. The rice will finish cooking, the mushrooms and onions will roast and get golden brown, and the dish comes together BEAUTIFULLY.

side view of mushrooms topping baked rice casserole.

I adore the flavors here. The beefy and buttery rice and spices give a distinctly holiday feel to the dish, and the mushrooms and onions on top are so savory and earthy.

You. Will. Love. This.

Storage and Make-Ahead Instructions

You can a thousand percent make this in advance and heat it up right before you eat, even in the microwave if you need to for the sake of space. The leftovers are great hot or cold, and with easy turkey gravy drizzled over the whole thing....stahhp.

Leftovers of this rice keep really well in plastic or glass storage containers for up to 5 days. If the rice seems dry when you reheat it, cover it loosely with a damp paper towel to re-steam the rice and bring it back to life.