In a large bowl, combine the flour, sugar, baking powder, pie spice, salt and baking soda. In another bowl, combine eggs sweet potatoes, pineapple and oil. Stir into dry ingredients just until moistened. Fold in walnuts and raisins. Fill paper-lined muffin cups three-fourths full.
Bake at 350° for 20-24 minutes or until a toothpick inserted in the center comes out clean. Cool for 10 minutes before removing from pans to wire racks to cool completely.
In a small bowl, beat cream cheese and butter until fluffy. Add the confectioners’ sugar, pineapple and vanilla; beat until blended. Frost cupcakes.