Put the flour, salt, dry yeast and spice mixture in a bowl and mix well. Mix with buttermilk and warm water and work into a dough (e.g. knead well with a dough hook in a food processor or knead with your hands).
Add the walnuts and place the dough in a greased and floured loaf pan. Cover and let rise for about 1/2 hour.
Then place in the preheated oven with a bowl of water. First bake for approx. 40 minutes in a preheated oven at 200 ° C, then switch the temperature down and finish baking at 150 ° C for approx. Another 20 minutes.