Prepare the marinade by mixing the mustard, oil and thyme together. Season the pork loin with salt and pepper. Spread the marinade on the entire outside surface of the pork loin. To roast on the grill, use the indirect heat cooking method - with the pork on the side of the grill without the heat source. Roast at 350 degrees for 25 minutes per pound.

To prepare the sauce, sauté sliced mushrooms in a skillet with the butter. When mushrooms are done add flour. Stir to incorporate the flour with the mushrooms. Add the chicken broth and the cream. Whisk the sauce while heating. When the sauce is hot and thick, add the cheese.
Slice the pork loin and serve with the gorgonzola mushroom sauce.

Serving Ideas: Serve with rice pilaf.