Bone broth AND any bone in slow cooked meat, the marrow seeps out into the gravy and if it doesn't lucky you will get to suck out the juices from those juicy bones. There is a French dish, can't remember the name, sorry, but scrape the marrow out some chunky bones after loosening it up in a hot oven for 30 mins or so. Chuck said marrow in a frying a pan and cook it further with garlic, shallots and a dash of red and season. Flash fry a steak, chuck it over, little bit of parsley. Whilst not full on gelatin, there is some but marrow! Just yum. A very simple and cheap way for some gelatin according to Weston Price foundation is Spam. Yes, sing along with Monty Python and indulge in a post war favourite. Apparently as a ration for troops during the war years, gelatin was added to the mix of cheap cut meat to add in some further nutritional benefit And still is, as it is used to hold the lot together in those tins. And another way is a bag a jelly babies. Not only gelatinous but comes complete with a sugar hit......I'll get my coat!