Preheat oven to 450 F (225 C).

Line 2 baking sheets with aluminum foil and spray with non-stick cooking spray.

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

Spread sweet potatoes on foil in a single layer on both baking sheets, without overcrowding. Bake until cooked and crisp, about 20 minutes, stirring halfway through.

Place blue cheese dressing in bowl and serve as a dipping sauce, or drizzle dressing over fries and serve.