In a medium bowl, stir together,1 cup Ile de France Roquefort, creme fraiche, sour cream, vinegar and Worcestershire sauce until combined.
Preheat grill or grill pan over medium-high heat. Oil grates right before using. In a large bowl, mix together ground chicken, scallions, celery, 2 Tbsp. pepper sauce and 3/4 cup Ile de France Roquefort just until combined. Shape into 6 patties, about 4" in diameter.
Grill burgers for 5 minutes or until browned; flip burgers and brush with remaining 2 Tbsp. pepper sauce. Grill 5/7 minutes more, or until browned and cooked through. (Temperature should read 165 F on instant read thermometer.) If desired, split rolls and place face-down on grill, turning to brown slightly about 1/2 minutes.
Place romaine and burgers on bottoms of rolls. Top each with 1 Tbsp. Ile de France Roquefort sauce and remaining cheese and cover with tops of rolls. Serve burgers with carrot and celery sticks and remaining sauce.