Smoked Turkey Sandwiches with Blue Cheese and Red Onions

Name: Smoked Turkey Sandwiches with Blue Cheese and Red Onions
Yield: Makes 4 Servings
Ingredients: 2 large red onions, cut into 1/3-inch-thick slices; Olive oil; 1 cup crumbled Maytag blue cheese; 3 tablespoons sour cream; 1 tablespoon minced fresh thyme; 8 5x3x1/2-inch slices multi-grain bread; 8 radicchio leaves; 3/4 pound sliced smoked turkey; 2 tablespoons Dijon mustard