| 1 | Preheat the oven to 375 °F. |
| 2 | Sift the flour, soda, and salt together, and set aside. |
| 3 | Work the shortening and butter together, with a spoon, until fluffy and creamy. |
| 4 | Add the sugar slowly, continuing to work until light. |
| 5 | Then add the egg yolk and beat until light and fluffy. |
| 6 | Add the flour mixture alternately with the buttermilk, beating well after each addition. |
| 7 | Stir in the vanilla and then gently fold in the stiffly beaten egg white. |
| 8 | Drop by rounded tablespoonfuls 3 inches apart on a greased cookie sheet. |
| 9 | Flatten with a spatula to ?inch thickness. |
| 10 | Bake in the preheated over for 20 minutes or until done. |
| 11 | Makes 18 3-inch cookies. |
