1. Wrap buns in aluminum foil; place pecans on a baking sheet.
2. Bake buns and pecans at 350° for 8 minutes. Remove pecans from oven, and set aside; leave hamburger buns in oven.
3. Combine ground turkey and next 4 ingredients in a large bowl. Shape into 6 (3/4-inch-thick) patties.
4. Cook patties in a large skillet coated with cooking spray over medium heat 6 minutes on each side or until done.
5. Remove buns from oven. Spread 2 heaping teaspoons Cranberry Mustard on each side of bun halves. Arrange half of spinach leaves evenly on bottom halves; top with turkey patties, toasted pecans, remaining spinach leaves, and remaining bun halves. Serve with remaining Cranberry Mustard, if desired.