1. Preheat the oven to 350 degrees F.
2. Sift the flour, baking soda, and salt into a bowl.
3. With a handheld or standing mixer, beat together the shortening and butter.
4. Add the 1 1/2 cups sugar and continue beating until light and fluffy, about 5 minutes.
5. Add the eggs, 1 at a time, beating well after each addition. Add the flour mixture and blend until smooth. Add vanilla, beat well.
6. Mix the 3 tablespoons sugar with the cinnamon in a small bowl. Roll the dough, by hand, into 1 1/2-inch balls.
7. Roll the balls in the cinnamon sugar.
8. Roll the balls, and spacing them evenly on unlined cookie sheets.
9. Bake until light brown, but still moist in the center, about 9 minutes. Cool on a rack.