i have one that i make just like my sausage gravy recipe.
I cook down a couple squirrels in the pressure cooker, then strip all the meat and give it a quick chop to make it a little finer. Put in a pan with a little onion and saute till hot again, and pour in a can of evap milk. add enough regular milk to make the volume you want...I like mine meaty so i add less milk. season with salt and pepper, then when boiling thicken with cornstarch or arrow root just like you would any other gravy.
If you wanna get creative, you can use the roux method...i'm not gonna get into making a roux - google it. I don't care for the flour flavor personally.
from here, sky is the limit. My son likes when we mix some veggies into the gravy and put biscuits on top and bake till the biscuits are done and golden...or just put them on the top of the gravy, lid and eat dumplings. Easily one of the most versatile quickee methods of cooking tree rats.
If you don't want a white creamy gravy, you can use the pressure cooker juices to make your gravy, just make sure you skim the fat from it...the fat adds a NASTY flavor to the gravy.
Jaydog..from a chefs point of view the roux would make a "better" gravy. As with all starch thickeners...they have to be "cooked" to get rid of that flour taste. Arrowrrots advantage is the lower temp it takes to thicken a liquid. Im curios now, im going to have to try this and let you know how I make out. The cornstarch and water(liquid) would be called a slurry, while a roux is fat(butter) with flour.