For cookies: Cream butter or margarine with brown sugar. Add 1 egg and mix well. Stir in melted chocolate, baking soda dissolved in milk, flour, dates and nuts.
Using a small tablespoon, drop dough on lightly greased cookie sheet or parchment lined cookie sheet one inch apart. Bake at 350 degrees F for 15-20 minutes. Place cookies on cooling rack over piece of wax paper when done.
Frosting: Combine egg, melted chocolate, milk or half-and-half, melted butter and powdered sugar until smooth. Using a knife or spatula frost cookie with frosting and let cool until frosting is set.