Combine ground beef and sausage in a large bowl. Shape mixture into 12 (2 1/2-inch) patties, and place on a large baking sheet. Sprinkle patties evenly with Cajun seasoning. Cover and chill up to 1 day, if desired.
Grill, covered with grill lid, over medium-high heat (350° to 400°) 5 minutes on each side or until no longer pink in center. Serve on split rolls with green leaf lettuce and Easy Rémoulade.
Easy Rémoulade: Stir together 3/4 cup light mayonnaise, 2 Tbsp. Creole mustard, and 2 Tbsp. chopped fresh parsley. Cover and chill 30 minutes or up to 3 days. Makes 1 cup. Prep: 5 min., Chill: 30 min.