Directions

1. Coat a large skillet with nonstick cooking spray. Shape beef into 4 (4-ounce) patties. Sprinkle both sides with Cajun seasoning.
2. Cook over medium-high heat 6 minutes per side or until an instant-read thermometer registers 160°F.
3. Meanwhile, for the blue cheese sauce, in a small bowl stir together mayonnaise, cheese and mustard. To serve, place burgers on toasted buns and top with sauce, lettuce, tomato and onion.