1Heat oven to 450°F. Lightly spray 2 (15x10x1-inch) pans with cooking spray. In large bowl, toss sweet potatoes, onion, 2 tablespoons of the oil and 3/4 teaspoon of the salt. Arrange vegetables in single layer in pans.
2Roast uncovered 25 minutes. Remove onion from pans; set aside. Stir sweet potatoes. Roast 10 minutes longer or until browned.
3Meanwhile, in 10-inch nonstick skillet, cook bacon over medium heat 10 to 12 minutes or until crisp. Drain on paper towels. Crumble bacon; set aside. Reserve 2 tablespoons drippings in skillet. Add remaining 1/4 cup oil, remaining 3/4 teaspoon salt, the vinegar, mustard and pepper to drippings in skillet; stir well.
4Transfer vinaigrette to large bowl. Add roasted sweet potatoes, onion, bacon, pecans and raisins; toss gently to coat.