I found this recipe on the Will Cook For Friends blog. These pumpkin & peanut butter dog biscuits are safe for dogs with sensitive stomachs.
The ingredients are a little pricey for dog treats -- specifically the rice flour (I ordered it from Target.com) and the natural peanut butter (some natural peanut butter has sugar so you have to check the ingredients).
These were pretty easy to make. I found that I needed to add a little extra pumpkin puree in order for the dough to hold together.
I found a Wilton 3" dog bone cookie cutter at Joann's in the baking section. This recipe made 18 biscuits with that cutter. (good size for medium to large dogs)