Ingredients

3 tablespoons vegetable oil, divided

4 pounds cross-cut beef short ribs (flanken style), about 1 1/2-inch-thick, cut into 2-bone pieces

Kosher salt and freshly ground black pepper

3/4 pound shiitake mushrooms, stems chopped, caps sliced, divided

1 bunch scallions, whites chopped, greens thinly sliced, divided

1 1-inch piece peeled ginger, thinly sliced

2 cups (or more) low-sodium beef or chicken broth

1/2 cup reduced-sodium soy sauce

1/3 cup dry sake

1/4 cup (packed) dark brown sugar

3 whole star anise

1 cinnamon stick

8 ounces wide rice noodles, cooked according to package directions

Preparation

Place a rack in lower third of oven; preheat to 325°. Heat 1 tablespoon oil in a large heavy pot over medium-high heat. Season short ribs lightly with salt and pepper. Working in batches, cook short ribs, reducing heat as needed to avoid overbrowning, until brown on all sides, 10-12 minutes per batch. Transfer short ribs to a plate; drain all but 1 tablespoon drippings from pot. Add shiitake stems, scallion whites, and ginger to pot. (Cover and chill remaining mushrooms and scallions.) Cook, stirring often, until fragrant, about 2 minutes. Add 2 cups broth, soy sauce, sake, brown sugar, star anise, and cinnamon; bring to a simmer. Return short ribs to pot, nestling them bone side up in liquid in a single layer. Cover pot, transfer to oven, and braise until ribs are fork-tender, about 2 1/2 hours. Using tongs, transfer ribs to a shallow baking dish bone side down. Strain liquid from pot through a fine-mesh sieve into a large measuring cup; discard solids. Skim fat from cooking liquid. Add broth as needed so liquid measures 1 1/4 cups and pour over ribs. Let cool completely, then cover with foil and chill for at least 3 hours. DO AHEAD: Ribs can be cooked 2 days ahead. Keep chilled. Preheat oven to 350°. Bake short ribs, covered, until heated though, about 25 minutes. Remove 1/2 cup liquid from baking dish; set aside. Heat remaining 2 tablespoons oil in a large skillet over medium-high heat and cook shiitake caps until brown and tender, about 3 minutes. Add reserved braising liquid and all but 1 tablespoon scallion greens and season with salt. Place cooked noodles on a large, deep platter. Arrange short ribs on top of noodles; drizzle sauce from dish over. Spoon mushrooms with sauce over. Sprinkle with remaining scallion greens.