01 - Preheat the oven to 350°F. Grease and flour a 9x5-inch loaf pan or line it with parchment paper.
02 - In a large bowl, whisk together flour, sugar, baking powder, baking soda, and salt.
03 - In a separate bowl, whisk buttermilk, vegetable oil, eggs, vanilla extract, and orange zest if using.
04 - Pour wet ingredients into dry ingredients and gently fold until just combined, avoiding overmixing.
05 - Fold in dried cranberries and chopped walnuts carefully.
06 - Pour batter into prepared loaf pan and smooth the surface evenly.
07 - Bake for 50 to 60 minutes, or until a toothpick inserted in the center comes out clean.
08 - Allow the loaf to cool in the pan for 10 minutes, then transfer to a wire rack to cool completely before slicing.