1/2 c. butter (room temperature)
1/2 c. shortening
1/2 c. firmly packed brown sugar
1/4 c. granulated sugar
2 1/4 c. flour
1 tsp. salt
Preheat oven to 300 degrees. Mix first four ingredients in large bowl on low to medium speed, or mix by hand with spoon. Add flour and salt. Dough will be crumbly and dry, use hands to completely mix. On a lightly floured surface, roll prepared dough into a 15 x 7 1/2 inch rectangle. Cut into 1 1/2 inch squares. On an ungreased baking sheet, place squares approximately 1 inch apart. Bake 25 minutes or until set. The shortbread will brown little and shape will not change during cooking process. Remove to wire rack.