Heat oven to 425°F. Position two racks in the middle of your oven.

FOR THE CRISPY SHROOMS: Line two sheet pans with parchment paper and scatter with mushrooms. Drizzle about 2 tablespoons of olive oil on each sheet pan, toss, and roast in the oven for 25–35 minutes, until the mushrooms are browning and starting to crisp. Remove from the oven and set aside.

SHROOM DRESSING: Whisk together 1 tablespoon of olive oil, 2 tablespoons of white miso, 1 tablespoon of rice vinegar, 2 teaspoons of white sugar, and 1 teaspoon of soy sauce. Set aside for later.

As the mushrooms roast, heat 3 tablespoons of olive oil in a large skillet over medium-high heat. Add the Chinese sausage and cook until partially done. Stir in the onions and let them cook undisturbed for 2 minutes. Reduce heat to medium-low and continue cooking the onions for an additional 8 minutes. Add the garlic and cook for 5 more minutes, then increase the heat to medium-high.

Stir in rice and cook for 1 minute. Add white wine and cook for about 1 minute, scraping up browned bits, until reduced by about half. Add 3½ cups of broth, ¼ cup of white miso, and 3 tablespoons of soy sauce. Bring to a boil, then cover and reduce heat to low. Simmer for 10 minutes.

After 10 minutes, uncover the rice, stir gently, then place in the oven and bake for 15 minutes.

Remove the pan from the oven and turn the broiler on high. Broil for 4–6 minutes, watching carefully, until rice is crisped and deeply browned.

Just before serving, stir the roasted mushrooms, sliced scallions, and the miso dressing together and spoon over the crispy rice.