In the Instant Pot, combine the red onion, jalapeño, garlic, ginger root, soy sauce, brown sugar, beef stock, sesame oil, and rice wine vinegar.
Add the beef stew chunks and stir to combine. Seal the Instant Pot. Select manual setting and adjust pressure to high. Set timer for 35 minutes.
When cooking is finished, let pressure release naturally for 15 minutes. Then manually release the remaining pressure.
Mix the cornstarch with 2 tablespoons of water. Set aside.
Remove the lid of the Instant Pot and put the meat in a large bowl.
Select the high sauté setting and stir in the cornstarch slurry. Continue cooking for 2 to 3 minutes or until the sauce is thickened.
Pour the sauce over the met.
Serve the stew in bowls and sprinkle with sesame seeds and scallions.
