Preheat oven to 350F degrees and line a 9x5 metal pan with parchment paper and spray the ends. I like to leave my edges high for easy removal after baking. In a small bowl add frozen cranberries and 1 tablespoon all-purpose flour. Mix to combine, then set aside. In a medium bowl whisk all-purpose flour, baking powder and salt. Set aside. In a large bowl add granulated sugar, buttermilk, vegetable oil and eggs. Whisk well until combined.

Transfer dry ingredients into the wet ingredients and mix with a spatula until there are no dry streaks. Fold in cranberry sauce then frozen cranberries. Pour batter into prepared 9x5 pan and bake for 60-65 minutes or until a toothpick comes out with moist crumbs from the center. Leave the pan for 10-15 minutes on a wire rack before removing the loaf and allowing it to cool fully on a wire rack.