Holy cow my lamb tendons made the firmest gelatin! First I soaked them for 24 hours to get the blood out changing the water out a couple of times. It makes a clearer broth doing this step. I cut the tendons in smaller pieces and cooked them for 5 hours. I still had about a third of the tendons that didn’t cook down so I added them to a new batch of beef bone broth I’m cooking today. 
Author
Cari