Keep the oven for preheating at 180 °C.
Add honey to buttermilk. Stir it to mix it.
In a large mixing bowl, add whole wheat flour, All-purpose flour, salt, cranberries, and baking soda.
Add honey and buttermilk solution to it. Mix it.
Add butter to the dough. Mix it well into the dough.
Knead the dough for 2 minutes and then shape it into a log.
Place the shaped dough into a lined loaf tin.
Seam side should face down. Using a sharp knife, slit the dough lengthwise.
Bake it in a preheated oven at 180 °C for 30 minutes.
Once baked, remove the tin from oven.
De-mold the bread and place it on a wired rack.
Let the bread come to room temperature. Slice and serve.