In a bowl, add the freeze dried sausage with two cups of water. Let the meat hydrate for about 10 minutes. Towards the end of the 10 minutes, add the freeze dried mushrooms and onions to the meat and water bowl. Let them sit for a couple minutes. Drain the water from the bowl and set aside for thinning the gravy later. In a large saute pan, add the butter and bring to medium-high heat. Add the hydrated sausage/onion/mushrooms to the pan and saute. Add the seasonings to the meat and continue to cook for a few minutes. Add the heavy whipping cream and turn the heat to low heat. Let the gravy simmer until ready to serve.
If you are using fresh pork, onions and mushrooms, saute the ground pork first until golden brown and then add the onions and mushrooms. Continue to saute in the butter and then continue the recipe as indicated above.