In an Instant Pot, add the beef, bones, onion, peppercorns, salt, and water. Cover and set to Meat/Stew (or Manual at high pressure) for 30 minutes.
While the stew is cooking, peel and quarter the potatoes. Core the cabbage, and cut into 1 to 2-inch chunks.
When the Instant Pot beeps, allow pressure to release naturally. Carefully open the lid. You may want to scoop out the bones and meat to make room for the vegetables.
Add the vegetables after the meat/stew is done. Here are two options:Sauté mode option: Set to Sauté mode at the default setting, then add the potatoes and cabbage. Leave the lid off. Cook until potatoes are fork-tender, this should not take 30 minutes. Turn off the Instant Pot. Add more salt to taste.Manual mode with Quick Release option: Add the potatoes and cabbage. Cover and set to Soup (or Manual at high pressure) for 3 minutes. When the Instant Pot beeps, very carefully do a Quick Release using the back of a spatula or wooden spoon.
Serve warm and enjoy!
Notes
Cook Time = time to build pressure + cook time at pressure + time to release pressure + sauté time