Preheat broiler. Spray a baking pan with cooking spray. Peel and core pears. Slice lengthwise and arrange slices in one layer on the baking pan. You should get at least 8 slices of pear per pear. Spray the pears with cooking spray.

Broil until pears turn golden brown on both sides. This may take 4-5 minutes per side. Watch carefully so they don't burn.

Put walnuts in a non-stick frying pan. Heat walnuts over medium high heat, stirring often. Remove from heat when they start turning browner and you can smell them.

Spread prosciutto on a microwaveable plate in one layer. Microwave until the slices are crisp and brittle. This takes about 4 minutes but check them often since microwave strengths vary. Allow slices to cool and them crumble them.

Bring port and shallots to a boil over medium high heat in a saucepan. Reduce heat and simmer until port is reduced by half (about 10 minutes). Strain the port and allow to cool. Discard shallots. Whisk remaining dressing ingredients together just before serving.

Toss greens, prosciutto, walnuts and blue cheese together. Divide evenly among 6 plates. Divide pear slices evenly and mound them in the center of the salad plate. Drizzle dressing over the salad just before serving.