Gradually, add the flour mixture to the creamed butter. 

Divide the dough in half and shape into discs. Wrap each one separately in plastic wrap and refrigerate for 1 hour.

After the dough has chilled, remove it from the refrigerator and let it stand at room temperature for 15 minutes. 

Between two sheets of waxed paper, roll out each disc, one at a time to a 12×10-inch rectangle. Don’t worry about perfect. You can trim it a little to square it up if needed.

Make the cinnamon sugar filling by combining the brown sugar, butter and cinnamon in a small bowl. 

Spread half of the mixture onto the rectangular piece of dough and spread out right to the edges. Starting at the long side, roll up the dough. When you first start to roll, press down lightly to pinch it into place. This will make it nice and tight in the middle. Continue to roll up the dough. Wrap the log in plastic wrap and refrigerate for 30 minutes. 

Repeat with second disc and wrap that log in plastic wrap and refrigerate for 30 minutes. 

Cut rolled logs into 1/4-inch thick slices and place cut side down on parchment paper-lined or greased baking sheets. Place the cookies one inch apart. 

Bake, one sheet at a time, in 375°F oven for 9 to 10 minutes. The bottoms and edges will be lightly browned.

Cool on wire racks.