In the bowl of a stand mixer, using the paddle attachment, combine 2 ½ cups flour, yeast and salt. Mix in sour cream and softened butter to form a soft dough.

Switch to the dough hook and mix in the remaining flour a little at a time, to make a soft dough that’s not sticky to the touch, adding more or less flour as needed.

Knead the dough for 5 minutes. Cover the dough and refrigerate for 3-5 hours, or overnight.

Combine sugar and cinnamon in a small bowl, mix well.

Mix flour, 1 ½ cups cinnamon sugar and softened butter in a medium bowl. (Reserve some cinnamon sugar to use later.) Mix the filling until it looks like clumpy, damp sand. Set aside.

Preheat the oven to 350°F. Divide the refrigerated dough into four equal pieces.

On a floured work surface, roll out the dough into a large rectangle. The dough should be thin, but not transparent.

Spread ¼ of the filling mixture across the rolled-out dough in an even layer. Spread the filling to the edges on the short sides, keeping 1 inch of pastry dough uncovered along the long edges. Sprinkle cranberries (raisins) evenly over the top, if using.

Start at the long edge and slowly rolling the dough in to a log. Making sure the filling stays evenly distributed. Roll all the way across until you have a long, thin loaf. 

Pat down the loaf with your palm and fingers so that it flattens out a bit (just a bit). Apply egg wash with a pastry brush. Sprinkle on a tablespoon of cinnamon sugar.

Use your crinkle cutter (or serrated knife) to cut the loaf into 8 equally-sized pieces. Put onto an ungreased cookie sheet (I used parchment paper).

Repeat with remaining dough. Bake for about 30 minutes, until the tops are golden brown. Remove to a wire rack to cool complete.