I clipped this out of the paper years ago. It's got a butt-load of oil/butter, but they're just so light and yummy. I think I originally made them without thinking about that until after I got started and then they were just so good I couldn't resist keeping the recipe.
2 cups flour
1 tsp. each: baking soda, cream of tartar
1 1/2 sticks unsalted butter, softened
1/4 cup solid vegetable shortening
1/2 cup each: packed light brown sugar, and white sugar
1 large egg
1 tsp. vanilla
Heat oven to 350 degrees. Grease baking sheet(s). Sif together flour, baking soda and cream of tartar; set aside.
Beat together butter, shortening and both sugars in large bowl of an electric mixer on high speed until light, 2 minutes. Add egg and vanilla and mix well. Stop mixer and add flour mixture. Mix on low speed just to combine.
Roll into balls and arrange on baking sheet, 2 inches apart. Dip a potato masher or fork into sugar and use to flatten cookies. (or just roll in sugar)
Bake until light colored 12 to 15 minutes. Transfer to wire rack and cool.