Preheat the oven to 350℉. Line a baking sheet with parchment paper or a silpat mat.
In a bowl of a stand mixer, add all the ingredients and mix until all of the ingredients are well-combined and come together into a ball. If you do not have a stand mixer, just use a sturdy wooden spoon. The batter is too thick to use a traditional hand mixer.
Transfer the dough to a floured surface. Roll the dough to ¼-inch thickness.
Use a cutter to cut the dough into shapes (use a dog bone cutter or round or whatever you prefer!) Transfer the cutouts to the prepared baking sheet.
Bake for 15 minutes. Turn the biscuits over, and bake for an additional 10 minutes. Cool on a rack.
Notes
To cook a sweet potato: Peel a medium size sweet potato and dice it. In a saucepan, with 1 to 2 inches of water boil the sweet potato until cooked. You should be able to insert a fork easily (15 to 18 minutes). Drain the water and mash the potato to a soft mixture, with a fork or a potato masher.
How to store dog biscuits: Keep some of these biscuits out and ready for your dog. Put the rest in a sealed container or freezer zip bag, and store in the freezer. Take a few out, as you want to share with your dog (I'd say take out 10 at a time and keep them at room temperature).