Make the Dough

1. In the bowl of a stand mixer, sift the flour, potato flour and dry milk. Add the rest of the dough ingredients and knead until a soft, smooth dough forms (about 5 minutes).
2. Place the dough in a lightly greased bowl, cover and let rise for 60 minutes or until doubled in bulk.

Make the filling

1. While the dough rises, put the melted butter into a medium bowl and add the remaining ingredients, stirring until the mixture is the texture of damp sand. Set aside.
2. Lightly grease a 9” x 13” baking tin. 

Assemble the rolls

1. Transfer the dough to a lightly greased work surface and press it into a 10” x 16” rectangle about ½” thick.
2. Brush the dough with the beaten egg and sprinkle it with the filling, covering all but a ½” strip along one long side.
3. Starting with the filling-covered long side, roll the dough into a log.
4. Score the dough lightly into twelve equal 1 ½” pieces. Cut the dough at the score marks. (TIP: dental floss will give you the cleanest cut: pull off a long piece of floss, loop it underneath the log at the score mark, and pull the ends in opposite directions to cut the dough). A bench scraper or sharp knife will work if you don’t have dental floss. 
5. Tuck the rolls onto the prepared pan and cover with lightly greased plastic wrap or a reusable cover; let them rise for about 45 minutes.
6. About 20 minutes before you’re ready to bake, position a rack in the top third of the oven and preheat the oven to 375°F.
7. Bake the rolls for 14 to 18 minutes until they’re a light golden brown, and a digital thermometer inserted into the centre of one roll reads 190°F.
8. Remove the rolls from the oven, place the pan on a rack and let cool for 10 to 15 minutes before icing.