Preheat oven to 350. Grease 8 x 4" loaf pan-line bottom with wax paper. Pour boiling water over dates--let soften. With elec. mixer, or by hand, beat butter untill creamy in lge. bowl. Gradually beat in the sugars and cream well; beat in the egg. Beat in the dates and their liquid (at lowest speed). Sift together flour, salt, baking powder and soda and add gradually, on lowest speed to the creamed mixture; stir in the nuts. Turn into greased loaf pan. Bake in center of oven 45 min., or until cake tester inserted in middle of loaf comes out clean. Cool loaf in pan on rack for 10 min. and turn out on rack to cool. Wrap airtight--will keep for at least a week, referigerated. Longer storage, freeze.