Place the onion, celery, sage, rosemary and garlic in a casserole with the oil over medium high heat. Add the pork loin and brown on all sides for about 15 minutes. Season with salt.
Dilute the 2 tablespoons of mustard in a little bit of hot water. Add this mixture to the casserole. Let everything cook on low heat for about 2 hours, covered, turning the pork loin every once in a while.
Slice the pork and place the slices on a serving dish. Add a few tablespoons of cream to the sauce and stir well. Pour the sauce over the pork slices and serve.
I had a few problems with this dish. The sauce came out very bitter and I would guess that it was the fresh rosemary from my garden. I should have used dried rosemary in retrospect. Consequently, I had to doctor the sauce with a bit of brown sugar to remove the bitterness. I also used a grainy french dijon but I don't think that was the cause of the bitterness. I don't plan on making this again. Thanks for sharing. - 16 Sep 2012