In a large bowl, stir together the whole-wheat and all-purpose flours, sugar, baking powder, baking soda, and salt.

In a small bowl, whisk together the oil, orange peel, orange juice, and egg. Add this mixture to the flour mixture, stirring the two mixtures just to moisten the dry ingredients. Fold in the cranberries and nuts, and pour the batter into a greased 9 x 5 x 3-inch pan or two miniloaf pans.

Bake the bread in a preheated 350° oven for 1 hour (about 50 minutes for the small pans). Set the pan on a rack for about 10 minutes before turning out the loaf to cool completely. Wrap the bread well, and let it stand overnight before slicing it.