1 cup uncooked brown or white rice

3 tablespoons butter

1 medium onion, diced

1 pound crimini or white mushrooms, cleaned and sliced

3 tablespoons all-purpose flour

1/2 cup Marsala wine

3/4 cup whole milk

salt and pepper, to taste

4 ounces Gruyere cheese

Cook the rice according to package directions.
While the rice is cooking, preheat the oven to 350 degrees. Melt the butter over medium heat in a large skillet and add the onion. Cook until translucent. Add the mushrooms and cook until brown.
Sprinkle the mushroom and onion mixture with the flour. Cook and stir for one minute. Pour in the Marsala gradually and cook until thickened, then gradually stir in the milk and cook until thickened. Stir in half of the cheese. Add salt and pepper to taste.
Once the rice is cooked, stir the rice and mushroom mixture together. Pour into a 2-quart baking dish and sprinkle with the remaining cheese. Bake for 20-25 minutes, until bubbling. Serve immediately.