Ingredients
1  tablespoon ground cinnamon    
3  tablespoons sugar    
3 1/2  cups all-purpose flour, plus more for dusting    
1  teaspoon coarse salt    
2  teaspoons baking powder    
1/4  teaspoon baking soda    
1  cup (2 sticks) unsalted butter, cold, cut into small pieces    
1 1/2  cups buttermilk 

Directions   
  1.   Preheat oven to 500*F. In a small bowl, stir together cinnamon and sugar; set aside. In a medium bowl, whisk together flour, salt, baking powder, and baking soda. Add butter; using a pastry blender, cut butter into flour mixture until it is the size of peas. Add buttermilk; mix with a spoon just until it forms a sticky dough. 
   
  2.   Transfer to a lightly floured work surface, and bring dough together. Roll dough into an 8-by-11-by-3/4-inch rectangle; sprinkle 1/2 tablespoon cinnamon sugar in center section of rectangle. Use a bench scraper or a spatula to lift the ends, folding the rectangle like a letter into thirds towards the center. Before folding the second end over, sprinkle another 1/2 tablespoon cinnamon sugar onto opposite flap; fold second flap over. Give dough a quarter turn, and repeat the rolling, sprinkling, and folding. Transfer dough to a parchment paper-lined baking sheet, wrap in plastic wrap, and chill in refrigerator for 20 minutes.
    
  3.   Remove from refrigerator, and return to work surface. Roll to a 1/2-inch-thick rectangle, and repeat sprinkling and folding method as in step 2 (when rolling out the second time, do not fold). Cut out with a 2 1/4-inch round biscuit or cookie cutter, and transfer to a baking sheet. 
   
  4.   Sprinkle tops with remaining cinnamon sugar, and place in oven for 4 minutes. Reduce heat to 375*F; continue baking until biscuits begin to brown all over, 20 to 25 minutes. Remove from oven; cool on a wire rack. Serve warm.  Makes 15. 

Source:  www.marthastewart.com