Preheat oven to 425°; grease a 9 x 5 inch loaf pan or spray it with cooking spray.
Combine cornmeal, flour, brown sugar, salt, baking soda, and orange zest in a bowl.
Add in the cranberries and walnuts; stir to combine.
In a small bowl, mix the eggs and buttermilk with a whisk; add to the dry ingredients and pour the melted butter on top.
Stir just until all ingredients are moistened and thoroughly blended; don't overmix.
Pour batter into prepared pan; bake in the center of the oven for 35-40 minutes, until cornbread is golden around the edges and a cake tester inserted into the center comes out clean; let stand for 15 minutes before cutting into thick slices to serve.