When I cook heart for Ozzie, I do it to use for treats for training! (Best not to have bloody chunks of heart in your pocket!!) I dice into smallish cubes and sprinkle a little bit of garlic powder over the top. I have one of those mesh oven chip things, so I slow roast them on there on the lowest heat for anywhere between an hour and three, depending on the amount and size of the chunks! Basically just keep an eye on it and remove from the oven when firm and no longer dripping!
http://www.cn-ice.com/quickachips-me...ker-p-702.html
That's the thing I am on about!!