Prepare marinade by combining soy sauce and calamansi/lemon juice. Slice the onions into rings. Set aside.
Thinly slice beef chuck and marinade for at least 4 hours. This is very important to allow the meat absorb the flavors of the marinade.
Using Intant Pot, set to Sauté. Heat oil and brown each pieces of the beef. Do this in several batches to allow it to brown.
Still using the Sauté function after browning all the meat. Quickly sauté the onions until semi-translucent. Set aside.
Return the meat to the pot, add the marinades adding enough (half cup or less) amount of water to meet the minimum required liquid to pressure cook in the Instant Pot. (I also added some of the onions to add to the flavor while the meat is cooking.)
Set Instapot to Pressure Cook, adjust time to 8 minutes. Release vent after cooking.
Transfer to dish and top it with the remaining onions. Serve and enjoy.
