Line 2 or 3 baking trays with parchment. You should be able to get all the cookies on 3 trays.
In the mixer bowl, combine pumpkin, water, oil, eggs and sugar. Beat well until combined and smooth.
Stir in flax seeds and oats.
With mixer running at low speed add flour, I cup at a time, allowing each addition to become fully incorporated before adding the next. You can switch to your dough hook at this point.
After adding three cups of flour, at more only if dough appears to be soft and sticky. You want a stiff and firm dough. Kneed in mixer for a few minutes.
Flour your work surface liberally, and kneed dough a couple of times then roll out to about ½ inch thickness. Cut dough into desired shapes.
Place on baking sheets slightly apart, they will expand slightly as they bake. Bake at 375 for 35-40 minutes. They should be dry and golden brown.