Taylor Dukes Unflavored Bone Broth Protein
Homemade bone broth simmered long enough to gel; chicken feet or trotters when appropriate; grass-finished gelatin strips; collagen from real animal parts, not a dessert-flavored powder pretending to be ancestral.
A US source in the Tested Swaps directory. Check that it ships to Europe; where it does not, the directory lists a European alternative alongside it.