Preheat the oven to 350 degrees F (175 degrees C).

Whisk flour, oatmeal, baking soda, baking powder, and salt together in a large bowl.

Beat sugar and shortening together in a large bowl until smooth and creamy. Beat in molasses, eggs, and vanilla. Gradually beat in flour mixture. Stir in walnuts and raisins. Drop teaspoonfuls of dough onto ungreased baking sheets.

Bake in the preheated oven until slightly browned, 10 to 12 minutes. Cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.