In a large bowl, cream butter and sugar until light and fluffy. Add eggs, one at a time, beating well after each addition. Stir in buttermilk and molasses. Combine the flour, salt, ginger, baking soda, nutmeg and allspice; add to creamed mixture just until moistened Fold in dates and walnuts.
Fill paper-lined muffin cups three-fourths full. Bake at 350° for 20-25 minutes or until a toothpick comes out clean. Cool for 5 minutes before removing from pan to a wire rack. Serve warm.