Set the pot to saute and add the olive oil and 1 tbsp of the butter.
Season the steak and when the oil is hot, sear it on both sides. Remove and set aside.
Add the remaining butter and then the onions. Fry until the onions are softened (around 3 minutes).
Add the garlic, bay leaves cajun seasoning, Worcester sauce and stock to the pot. Deglaze if necessary before adding the meat back in.
Put the lid on and set on high pressure for 50 minutes. When the time is up, leave under pressure for a further 15 minutes and then do a quick release if necessary.
When the pin has dropped, remove the lid followed by the meat.
Set the pot to saute and remove around 6 tbsp of liquid to a small bowl containing the cornstarch. Mix together and then stir back into the pot together with the salt.
Whilst the gravy is thickening, shred the beef using a mixer or 2 forks.
Once the gravy has thickened, add around a quarter of it back to the meat and save the rest for dipping you're sandwiches.
Add the meat to French bread (or a hoagie sub in the US) and add your desired garnish (usually sliced tomatoes, shredded lettuce and pickles). Serve and enjoy.