Okay, I made my own beefheart mix two days ago...
I went to the butcher and got 2 pounds of trimmed beefheart. I paid a dollar more a pound to have him run it through the grinder a couple of times.
2 lb ground beef heart
1 - 12 oz package of frozen peas and carrots
1 bulb of garlic
1 1/2 pounds of shrimp
I thawed the veggies and prawns. Peeled the shrimp. Then I used a food processor to pulp everything. I mixed everything together in a bowl and then filled two large freezer bags. I bled the air out of the bags, spread them flat, and popped them in the freezer. The fish love it... I was going to add gelatin to firm things up but I didn't think it was really necessary.