Preheat your oven to 300°F (150°C).

In a large Dutch oven, heat 2 tablespoons of sesame oil over medium-high heat. Season the short ribs with salt and pepper and sear them for 4-5 minutes on each side until golden brown.

In a medium bowl, whisk together miso paste, soy sauce, rice vinegar, brown sugar, grated ginger, and minced garlic until smooth.

Deglaze the pan by pouring a splash of beef broth and scraping up any browned bits with a wooden spoon.

Return the seared ribs to the pot, pour the prepared miso sauce over them, and add the remaining beef broth to cover the meat.

Bring the mixture to a simmer, cover the pot, and transfer to the oven. Braise for about 3 hours until the meat is tender.

Remove the ribs, bring the remaining sauce to a boil, mix cornstarch with cold water and add to thicken the sauce.

Return the ribs to the sauce to soak up the flavors before serving. Garnish with green onions and sesame seeds.