- With the rack in the middle position, preheat the oven to 350°F (180°C). Line a baking sheet with parchment paper.
- In a food processor, place the flour, corn flour and oats. Process to a fine powder. Add the peanut butter and egg and mix until smooth. Add the water and mix again until it forms into a ball. On a work surface, knead the dough for 1 minute to give it elasticity.
- On a work surface lightly floured with whole wheat flour, roll out the dough to a 1⁄4-inch (5 mm) thick sheet. Using a bone-shaped cookie cutter, cut out the biscuits. Reuse the scraps. Place the biscuits on the baking sheet.
- Bake for 20 minutes or until the biscuits begin to turn golden brown and have fully dried. Let cool completely. Store in airtight bags or cookie tins.
- The biscuits will keep for several weeks in a cool, dry place.