In a large bowl, combine flour, oats, parsley, dry milk, salt and stir until mixed.
Add eggs and peanut butter and mix well. (Expect it to be crumbly!)
Add the cold water and mix until dough is cohesive.
Roll out dough approximately ¼” thick. It will look cracked with ragged edges but, no worries. I promise your pup won’t care.
Use your cookie cutter to cut out dog biscuits. If you don’t have a bone-shape cookie cutter, use whatever you have. Again, I promise your pup won’t care.
Repeat the process of rolling out the dough and cutting biscuits until you have no dough left.
Place the biscuits on a greased cookie sheet or one lined with parchment paper. It’s fine to put them pretty close together as they won’t expand much while baking.
Bake for 40 to 60 minutes. The baking time will vary depending on the size of the biscuit so after 40 minutes, check every few minutes until they are done. The biscuits are done when they are golden brown and dry and crisp all the way through.