12 soft white dinner rolls or slider buns 6 tablespoons Dijon mustard, divided 3/4 cup cranberry sauce 12 slices (about 1/4-inch-thick) leftover turkey 12 thin slices provolone Pepper to taste 4 tablespoons unsalted butter 2 tablespoons finely chopped onion 1 tablespoon poppy seeds 2 tablespoons Worcestershire sauce 1 teaspoon garlic powder Preheat the oven to 350 degrees.