Heat oven to 425°F. position 2 racks in the middle of oven.

Line 2 sheet pans with parchment paper & scatter with mushrooms. drizzle 2 tbsp olive oil on each pan, toss, & roast in oven for 25–35 minutes (rotating racks halfway), until the mushrooms are browning & starting to crisp. remove & set aside.

Meanwhile, whisk together 1 tbsp olive oil, 2 tbsp white miso, 1 tbsp rice vinegar, 2 tsp white sugar & 1 tsp soy sauce. set aside.

Heat ¼ cup olive oil over medium high heat in a large skillet or braiser. add onions & cook undisturbed for 2 minutes. lower heat to medium low & cook onions for another 8 minutes, until they soften & start to brown. add garlic & cook for 5 minutes.

Raise heat to medium high, stir in rice & cook for 1 minute. add wine & cook for about 1 minute, scraping up browned bits, until reduced by half. add 3½ cups broth, ¼ cup white miso, and 3 tbsp soy sauce. bring to a boil, cover & reduce heat to low. simmer for 10 minutes.

Uncover rice, stir gently to re-distribute the liquids, place in the oven & bake on middle rack for 15 minutes.

Remove the pan from the oven & turn the broiler on high. place an oven rack in the second slot from the top, place the skillet on the rack & broil for 4–6 minutes, watching carefully, until rice is crisped & deeply browned but not burned.

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