Step 1

Peel and quarter optional onion, and place in the bottom of the Instant Pot.

Step 2

If not cut in half, cut beef heart in half and remove any hard bits (it may already be trimmed and there is nothing to do).  Place in the Instant Pot on top of the onion if using, and sprinkle with sea salt.  Pour water around the salted beef heart.

Step 3

Place the lid on the Instant Pot, and set to 'seal'.  Cook on high pressure for 75 minutes on high pressure.  Allow pressure to release naturally for at least 15 minutes.

Step 4

Slice thinly against the grain, salt as desired, and enjoy.  The sliced pieces can be served as you would serve steak, topped with sauce like chili-lime mayo, salted, or even diced and added to stir fry or soup, or slice thinly and use as lunchmeat in sandwiches.