Preheat and Prepare: Preheat oven to 350°F (175°C). Grease a 9x5-inch loaf pan.
Mix Dry Ingredients: In a large bowl, combine flour, sugar, baking powder, salt, and baking soda. Fold in cranberries and walnuts.
Mix Wet Ingredients: In a medium bowl, whisk together orange juice, egg, oil, and orange zest.
Combine: Pour wet ingredients into dry ingredients. Stir gently until just combined—don’t overmix.
Bake: Spoon batter into the prepared pan. Bake for 50 minutes or until a toothpick inserted in the center comes out clean.
Cool and Serve: Let bread cool in the pan for 10 minutes, then transfer to a wire rack. Cool completely before slicing.