Growing up my dad always cooked hearts in the crockpot and that how we still do it, turns out great and makes fantastic sandwiches. Soak it in salt water over night, season it and crockpot it. A few years ago my dad tried an elk heart in a dutch oven while at elk camp, when they returned from hunting the heart was the size of a hardball and just as hard, needless to say, he went back to the crockpot