01 - Set the oven to 400°F and line a baking sheet with parchment paper.
02 - Whisk together all-purpose flour, whole wheat flour, sugar, baking soda, and salt in a large bowl.
03 - Stir dried cranberries and chopped walnuts into the dry ingredients, coating them evenly with flour.
04 - In a separate bowl, combine buttermilk, melted butter, and egg, whisking until blended.
05 - Pour wet mixture into dry ingredients and gently mix with a wooden spoon or hands until a shaggy dough forms; avoid overmixing.
06 - Transfer dough to a lightly floured surface and shape into a round loaf approximately 7 inches in diameter.
07 - Place loaf on the prepared baking sheet. Cut a deep X across the top and brush with additional buttermilk.
08 - Bake for 35 to 40 minutes until the crust is golden brown and a skewer inserted in the center comes out clean.
09 - Allow the bread to cool on a wire rack for at least 30 minutes before slicing.