I brought home an elk liver about 10 years ago, as my wife said she grew up on liver and onions, and so did I. She cooked up about have of it as she recalled how her mom always made. Either she didn't remember correctly or elk live is not to be consumed by humans.
As mentioned above, buttermilk gets rid of the bitterness.
Save a few bones for your dog (especially from the hind quarter). Bones contain essential minerals that aren't in regular dog food and they're clean nutrition too.