Cut the purple cauliflower in to small florets and steam until tender. Strain and put in ice water to stop cooking process. Take out after a couple of minutes so you don't lose too much of the purple color. Set aside.

Put the 2 tablespoons of olive oil in a skillet and add in the chopped walnuts. Toast for about 3-4 minutes (or you can toast them in the microwave). Remove the nuts from the skillet.

Add the chopped garlic and the chopped shallots to the pan along with the mushrooms, rosemary, thyme and sage; saute for 1 minute.  Stir in the white wine and the heavy cream along with the 1/2 c. Parmesan cheese and the dash of nutmeg. Salt and pepper to taste. Stir in the chopped chicken, optional.

While the sauce is cooking start a large pot of salted water and bring to a boil and cook your pasta al dente. When the pasta is done strain (reserve about 1 cup of the pasta water in case you need it to thin sauce -- I didn't) and toss pasta with the cooked purple cauliflower.

Gently pour the walnut sauce over the pasta and cauliflower and toss to mix. Pour into serving dish and garnish with some additional sage leaves and some extra chopped walnuts. Sprinkle with additional Parmesan cheese