Add in the peanut butter and hot water and stir well.
Once all of the ingredients are well incorporated, knead the dough a few times.
Roll out the dough onto a floured surface until it is about ¼? thick.
Use cookie cutters to cut out shapes and place onto a lightly greased baking sheet, or baking sheet with Silpat.
With a pastry brush, lightly brush egg onto top of each biscuit.
Bake for 30-40 minutes. After removing biscuits from the oven, cool on the baking sheet for at least one hour.
Notes
These homemade healthy dog biscuits should stay fresh for about one week if kept in an airtight container. You can also freeze them for up to 6 months.