In large bowl of an electric mixer, beat butter and sugar until creamy; beat in eggs and vanilla, then chocolate.
In another bowl, stir together flour, baking powder, and salt; gradually add to butter mixture, blending thoroughly.
Stir in dates and walnuts.
Drop dough by level tablespoonfuls onto greased baking sheets, spacing cookies about 1 inch apart.
Bake in a 350Â° oven for 13 minutes or until tops are dry and just set when lightly touched (cookies will be soft; do not overbake).
Transfer to racks and let cool.