Step 1

Adjust oven rack to lower-middle position and preheat oven to 325°F. Heat oil in an oven-safe Dutch oven over high heat until shimmering. Season meat generously with pepper, then sear until browned on all sides, about 4 minutes per side.

Step 2

Reduce heat to medium. Add garlic and ginger and cook, stirring constantly, until browned, about 2 minutes. Add mirin and scrape up any browned bits from bottom of Dutch oven. Add ponzu sauce, soy sauce, apple juice, sesame oil, 1/2 cup water, brown sugar, and vinegar and stir to combine.

Step 3

Bring to a simmer, cover, and transfer to oven. Braise, turning beef once and adding water if necessary to keep it halfway submerged throughout cooking, until beef is fork-tender, about 3 1/2 hours.

Step 4

Transfer beef to a platter and skim fat from cooking juices in Dutch oven. Taste cooking juices: If too concentrated, dilute to taste with water and/or mirin. Combine cornstarch with remaining 2 tablespoons water, whisking thoroughly to remove any lumps. Whisk cornstarch slurry into cooking juices, bring to a boil over high heat, and cook until gravy is thickened, about 2 minutes.

Step 5

Serve short ribs over rice, drizzled with gravy and garnished with green onion and pear.