Drain off 1/3 of the tomato sauce and keep.
Empty remaining contents of can into bowl and mash up.
Add flour and eggs.
Mix well, adding more tomato sauce or water if necessary until the mixture is a soft dropping consistency.
Place into a cake tin or baking tray and put into a moderately hot oven (Gas Mark 5, Celsius 190, Fahrenheit 375) for about ½ hour.
Remove from oven
Allow to cool slightly
Cut in to treat size pieces appropriate for your dog.
If you want a crunchy treat that can last longer then place back into oven until dried thought.