• Preheat oven to 350°F (180°C). Line a large baking sheet with parchment paper. Slightly oil paper with cooking oil spray. Set aside.
• In a large mixing bowl, beat egg, sweet potato puree, and peanut butter.
• Stir in the flour, quick oat, and cinnamon. Start stirring with a wooden spoon, then use your hand to knead the dough. If too dry or crumbly to form a ball, add 1-2 teaspoons of water to bring the ingredients together.
• Roll the dough ball into a 1/2-inch thickness, and using a dog cookie cutter, cut out bone shapes.
• Place the bone-shaped cookies on the prepared cookie sheet. They won't expand while baking but leaving half a thumb of space between each of them makes it easier to remove from the tray later.
• Bake for 25 minutes for softer cookies or up to 35-40 minutes for ultra-crunchy treats. Bake until golden brown, not burnt or too dark.
• Cool on the rack for 5 minutes before transferring them to a cooling rack.

Storage

• Store in a sealed jar at room temperature for up to 1 week or freeze and thaw the day before.