Preparation Preheat oven to 350°F. Spread walnuts on baking sheet. Bake until toasted, about 5 minutes. Cook bacon in heavy medium nonstick skillet over medium-high heat until crisp and brown, about 5 minutes. Using slotted spoon, transfer bacon to paper towels to drain. Coarsely chop bacon. Prepare barbecue (medium heat) or preheat broiler. Cut pears into 1/4-inch slices and spray lightly with nonstick spray. Grill or broil pear slices until brown in spots, about 2 minutes per side. Bring Port and shallot to boil in heavy medium saucepan; reduce heat to medium-low and simmer until reduced to 1/2 cup, about 10 minutes. Strain into large bowl; cool. Whisk oil and vinegar into Port. Season with salt and pepper. Add greens, cheese, walnuts, bacon and pears to dressing in bowl and toss to coat. Divide among plates and serve.