Step 1

Spray a 9x13x3-inch casserole dish with non-stick spray and preheat the oven to 375 degrees F.

Step 2

Melt one tablespoon of butter in one tablespoon of oil in a high heat pan such as cast iron or carbon fiber over medium high heat. Once hot, add mushrooms and cook for about ten minutes stirring often until well browned. Remove to a large bowl.

Step 3

Add remaining butter and oil to the pan and reduce heat to medium and add the onions.

Step 4

Cook onions for about five minutes or until they start to get soft then add garlic and cook for one minute. Add to large bowl with the mushrooms.

Step 5

Add the cut-up pot roast along with the parsley and provolone to the large bowl then toss to combine.

Step 6

Heat the bowl of meat and vegetables in the microwave for a few minutes to get the heat up and to accommodate the sauce and pasta.

Step 7

Place a large pot of water on to boil and once boiling, salt the water and add the pasta. Cook shy of fully cooked since the pasta will cook further in the oven and absorb some of the sauce.

Step 8

While the pasta cooks, in a medium sauce pan, heat broth, cream, Boursin cheese, one cup of the Parmesan cheese, salt, pepper, dry mustard and nutmeg and cook just to melt and combine. Remove from heat and add to the large bowl.

Step 9

Once the pasta is cooked, drain and add to the bowl with the other ingredients and stir to combine.

Step 10

Pour into the prepared casserole dish and cover with the remaining half cup of Parmesan cheese and bake for 35-40 minutes uncovered or until hot and bubbly and slightly browned on top.

Step 11

Serve immediately with more chopped parsley as garnish.