Yield: 16 cookies
¾ cup (1 ½ sticks) unsalted butter, at room temperature
½ cup (packed) dark brown sugar
1-¼ cups all-purpose flour
1 2/3 cups old-fashioned rolled oats (not the quick cooking kind)
½ teaspoon salt
1 teaspoon ground cinnamon
Preheat oven to 350 degrees F. Line a large rimmed baking sheet with parchment paper. Using an electric mixer fitted with the paddle attachment, cream together the butter and sugar until light and fluffy. In another bowl, combine the flour, 1 cup of oats, salt and cinnamon. Add to the butter mixture and stir until combined.
Finely grind the remaining 2/3 cup of oats in a food processor. Dust your rolling surface with some of the ground oats. Divide the shortbread dough in half and roll out each into a circle about 8 inches in diameter and 3/8 inch thick. Sprinkle the remaining oatmeal over the top of the dough and press it into the surface with the rolling pin. Using a sharp knife, cut each circle into 8 wedges. Prick each wedge all over with the tines of a fork. Transfer to the prepared baking sheet and bake until golden brown, approximately 18-20 minutes. Cool on a rack and then store in an airtight container.
Source: Sarah Leah Chase – Cold Weather Cooking – 1990