Set pressure cooker to saute and add olive oil. Add ground beef and break up, include diced onions + garlic and cook until meat is no longer pink on the outside. Then turn pot off. Use wood spatula to scrape any stuck on meat off bottom.
Pour in sauce and water, then pour pasta on the top and gently submerge into the liquid below. Do NOT stir.
Seal lid and steam valve and cook on high pressure for 6 minutes. Then do a quick release, lift lid and stir. Serve with shredded parmesan on top.