This was so simple and I know many have posted on making jerky treats just thought I'd add a specific recipe.
Beef heart is one of Bugsy's staples so I took a piece out of the freezer and sliced it thin, best width seems about 1/4 inch. I laid them out on a rack and put that on a shallow roasting pan and sprinkled a little garlic powder on them. Put them in a 200* oven for 4 hours.
Then I chose to cut them into bite size pieces for our training class. A smaller dog might like the whole piece as a chew. LOL DH considered eating them as very lean jerky.
Most of the pieces are crisp a few are just slightly chewy.
Now not sure they need to be refrigerated or not.