The last time I had heart, I used it to make liver pate. The trick to both the liver and the heart is not to overcook them. Think lightly seared, very rare on the inside.
I soaked both in a bowl of water for about 20 minutes to let the blood and other stuff out of it, and rinsed in the middle, then when ready, removed all the silver skin off them. The liver had a very light smell to it, almost like grape fruit, and I was very tempted to try to eat it raw. Maybe one day I'll work up the courage to do so. :)
I used this recipe here: http://farmlet.co.nz/?p=199 using both the heart and liver instead of just liver and ghee instead of butter. I probably used a lot more ghee, garlic, and wine than the recipe calls for.
Once the sauce reduces down a bit, I add the heart and liver, and I don't let it cook for very long, just let it get lightly coated in the sauce and cook it only for a few minutes on all sides before killing the heat and putting it all in the food processor.
I dump this into a pyrex container, and top it with tons of ground pepper. You can also add some cocoa powder and/or cinnamon. Once cooled, it goes in the freezer, so it can last a long time.
I occasionally chisel out a hunk of it using a knife, and put it in my lunch - since it's frozen, it keeps the rest of the lunch, usually a salad, cold, and by the time I'm ready to eat it, it's nicely thawed. It has a somewhat cheese like flavor to it, but it's really good.