Preheat oven to 450º Line 2 baking sheets with aluminum foil; spray with nonstick cooking spray.

In large bowl, combine sweetpotatoes, oil, flour and salt; toss until well-coated.

In a single layer, spread sweetpotatoes on foil without overcrowding. Bake until cooked and crisp, about 20 minutes, stirring halfway through. Repeat with remaining sweetpotatoes.

To make Blue Cheese Dressing: In a blender, place sour cream, buttermilk, half of the blue cheese, onion, lemon juice, Worcestershire, garlic, salt and hot sauce; whirl until smooth. Remove to bowl. Add remaining cheese; mix with spoon.