In a large bowl, cream butter and sugar until light and fluffy. Beat in the egg, sweet potato and vanilla. Combine the flour, baking powder, cinnamon, baking soda, salt and allspice; gradually add to creamed mixture and mix well. Fold in pecans and raisins.
Drop by tablespoonfuls 1 in. apart onto ungreased baking sheets. Bake at 375° for 10-12 minutes or until edges begin to brown. Cool for 1 minute before removing to wire racks. Store in an airtight container. Yield: 5 dozen.