Cream together the butter and sugar in a mixer. Add the egg and salt while continuing the blending. Then add the rice flour and about half the regular flour, a little at a time, until blended. Remove from the mixer and add the remaining flour, a little at a time, kneading with your hands, until the cookie dough is no longer sticky.
Flour a surface and divide the dough into 6 equal parts. Make each part into a ball and then roll each out with a rolling pin until each is about one half inch thick. Place the dough on a cookie sheet with a paper bag circle underneath the dough. (The paper bag helps to absorb some of the grease from the butter as the cookie bakes.) Score each circle into six pieces, scoring about 1/2 to 1/3 into the dough circle. Make designs on the circles with a fork. Sprinkle the top with colorful sugar.
Bake for approximately 30 minutes at 300 F, or until golden brown. Place on cooling racks and score the circles once again.
A note about the recipe from Nancy Sanders of Gurnee, Ill.
The Sanders's Scottish Shortbread has been our holiday cookie tradition for three generations. My husband's Granny, "Eleanor" McKay, emigrated from Scotland and brought the recipe with her.
I first became acquainted with the family cookie during the holiday season in 1976 when my husband and I began dating. The cookie is so wonderful because it is made with lots of butter, sugar, and colorful sprinkles and steeped in family love and tradition.
Eleanor's daughter, Janet, taught me how to make the cookie in 1980 during our first married holiday season together. I'd like to say that I learned how to make this cookie for the sake of family tradition, but actually I learned it because I wanted to keep our marriage together. My husband, back then, had some serious problems with sharing and he wouldn't share "our" holiday apportionment of the Sanders's Scottish Shortbread!
Thirty-one years have passed and the tradition of making Sanders's Scottish Shortbread is now my treasured responsibility. Janet, my dear mother-in-law, has been suffering from Alzheimer's for the last decade and it has become my honor to make this family cookie every holiday season for the Sanders family.
During my holiday cookie baking this season I plan to include my daughter, Kathleen "Eleanor" Ann Sanders, and I will make this shortbread cookie with her, as I pass the tradition down to the fourth generation of our family. (I will make a few extra batches as my husband still has problems sharing!)