So here's my story with heart and liver. Tried it for the first time last season with a whitetail.
Heart:
I can honestly say this was the best cut of meat I have ever had off a whitetail. I cut out the chambers and took any membrane off that I could find. Fried it in some olive oil, salt, pepper, a little garlic powder and fresh squeezed lemon. I couldn't believe what I had been missing all these years. Texture was tender as well!
Liver:
Totally different story. I tried taking off membranes but it didn't seem like I could peel it like I did the heart so I just ended up cutting them into strips. Fried them similar to the heart. And while the taste wasn't bad, the texture is what killed it for me. It was just a dense, almost crunchy, texture like I've never experienced before. I've eaten beef liver from the store plenty of times and liked it just fine (texture included), but I'm sure I did something wrong here to make it that bad. Any thoughts how to improve it?
(Also, I cooked both ~3-5 days after the kill, never frozen)