Preheat oven to 425° F. In a large bowl, toss olive oil, butternut squash and salt. Line a large, rimmed baking sheet with nonstick foil. Spread butternut in a single layer on baking sheet. Roast in oven about 25 minutes or until tender and beginning to brown around edges.
In a large, deep nonstick skillet or saucepan, over medium high heat, cook pancetta until fat has rendered and meat is crisp. Transfer to paper-lined plate. Add onion and garlic to skillet or saucepan; cook in pancetta drippings until tender, adding olive oil as needed. Add cooked pasta, cream and lemon juice. Toss to combine. Add reserved pasta water as needed. Cook until heated through. Stir in roasted butternut squash, pancetta, thyme, blue cheese and pecans.
Transfer to a large serving platter. If desired, garnish with thyme sprigs.