This cookie maker is a fun activity to do with your dogs. My two pugs actually sat and waited for them to cook while I "explained" to them what I was doing and that cookies were coming :D. The first time I used this, I made a recipe from the book (PB one with oats and flour) and the dough was very stiff and difficult to get into the hot mold. I ended up throwing out a lot of dough and stopping early because there were burnt spots on the cookies - I planned to make a bunch and give them as xmas gifts but had to cancel that plan due to this. My dogs still liked the cookies, however, and ate them all over the next week or so.
The second time I used this I modified a donut recipe from my Dash mini donut maker recipe book - leaving out sugar, butter and baking powder of course. I ended up using flour, added banana and left out the egg (I'm vegan), and used soymilk instead of milk and added PB and water to make a wetter dough - similar to a pancake dough.
I put the dough into a baggie and cut off the corner, then piped it into the bone shapes. It came out really well, like doggie banana bread. Much better than the first batch and my dogs love them. I cooked 4 min then flipped and cooked an additional 4 minutes.
I'm going to try making crunchy cookies again and follow the advice of a previous reviewer who recommended molding each cookie using the treat maker while still cold, then heating it up and adding each pre-formed cookie. Sounds like a good plan, hopefully won't burn this time!