Set Instant Pot to “saute” function. Add butter.
When butter is melted, add meat. Turn beef every 15-20 seconds or so until all sides are browned.
Add leeks and tomatoes and sauté for another minute.
Add beef stock, oregano and cumin.
Place lid on Instant Pot, turn to close, and set tab to “sealing”.
Press “meat/stew” setting (or high pressure for 20 minutes).
Allow to naturally release for 8-10 minutes before switching tab to “venting”.
Allow Instant Pot to release pressure and remove lid. Press “saute” function