Heat a tablespoon oil in the Instant Pot using the Saute Medium setting. Salt and pepper the ribs and add to the pot. brown thoroughly on all sides, moving as necessary. As the ribs brown, add in any vegetable scraps and if needed a little bit more oil. Once the ribs are well browned, remove them and the vegetable scraps and reserve.

Use about 1 1/2 cups of the liquid of choice to deglaze the pot, thoroughly scraping the bottom, removing all residue. Add the ribs and vegetables back in along with remaining liquid, 10  to 12 cups of liquid as desired. Note: hedge your bets on the brothiness of the soup; start with 10 cups and when finished adjust to your taste with a little more. Seal and set to Pressure High 35 minutes (may add up to 10 minutes if time is available). Quick-release when finished.

Strain the broth into a large container and set aside. Skim after the fat rises to the top. Remove the beef and cut into small cubes, removing any fat. Discard vegetable scraps.

In the meantime, add another tablespoon oil to the instant pot, set to Saute Medium. When hot, add the onion, celery, and carrots, cooking several minutes, stirring now and then until starting to soften and onion is translucent. Add garlic and stir until fragrant. Add tomato paste or ketchup and continue to stir until slightly darkened. 

Adjust the temperature of the Saute to High, add in the skimmed broth and cubed beef and allow to simmer until vegetables are tender. Add in salt and pepper to taste, then the noodles. Continue to simmer until noodles are cooked to the desired state, adding in the peas to heat through when noodles are nearly done. If you’ve reserved any broth, determine if you wish to add it at this point. Taste and adjust seasoning.