3 tins of sardines (I usually use 2 in oil and one in water)
3 eggs
Enough plain flour to get a spreadable consistency (you could use gluten-free or other flour options)
I spread the mixture on a baking sheet to about ½cm thick and bake in a medium oven about 180C (gas mark 4) for 1/2hr, or until firm
Cool down and cut into tiny pieces.
You can dry the cut pieces off for a while in a cool oven to improve their keeping quality or keep them very soft for easier swallowing when training.
A more recent variation I have used
Once all the ingredients are mixed to the spreadable consistency I have watered the mixture down until it is a little thicker than a batter and pour and spread onto pyramid pans (see below) or silicon dog treat baking trays could be used. This method gives you loads of tiny treats - you will be able to fill 2 - 3 pans with this volume.