For the topping, combine melted butter, honey, salt and peanut butter in a bowl. Stir to mix well. Leave aside.
Grease a round baking pan and lightly dust with some flour, shaking off any excess flour.
Sift both flours together into a mixing bowl. Add sugar, salt, milk powder, bread improver and yeast. Process with a dough hook at low speed for a minute. Add lukewarm water and fresh milk. Mix on medium speed for 3-4 minutes.
Add butter and continue to beat on low speed until a soft and pliable dough is formed.
Transfer dough to a lightly floured tabletop. Round up into a ball then place into an airtight plastic container. Cover and allow to proof for 40 minutes or until doubled in bulk.
Place dough on a lightly floured tabletop. Roll out into a flat rectangle. Brush dough with combined peanut butter mixture. Sprinkle with combined cinnamon and icing sugar and add raisins liberally around. Roll up tightly and cut into 2.5cm wide sections. Arrange the rolls in the prepared cake pan. Cover with cling film and leave aside to proof for about 20 minutes or until doubled in size.
Bake in a preheated oven at 190°C for 5-6 minutes. Remove and brush with combined topping. Sprinkle with chopped walnuts and continue to bake for another 15 minutes or until well risen.