Hi there! I know this is ages later but a couple weeks ago, we got a heart from a local butcher and had NO idea what to do with it. Found your step-by-step via Google and it made it so easy for us, and the marinade was awesome. Thank you!
We skipped the butter reduction because we're eating heart for health reasons (omg CoQ10!) :) We cut it into smallish chunks -- 1-2" squareish -- and put it on skewers with plenty of space, and onions in between. Marinated it overnight, grilled it really fast. It was delicious.
I'm so glad that my post was helpful to you, and thanks very much for taking the time to reply and tell me so!!!
Beef heart is very lean and very healthy. And it makes great jerky too, if you like to make jerky.
Welcome to the forum!!