In a large bowl, combine the flour, cocoa powder, salt, baking powder and soda; blending well and set aside. In a mixing bowl, beat together butter or margarine and sugar on low speed until fluffy. Add egg and vanilla; beat well. Gradually add dry ingredients to the creamed mixture; beat until smooth and well blended.

With hands, shape dough into 1-inch balls; place on ungreased baking sheet. Press down center of dough with thumb.

Drain Maraschino cherries well, reserving juice. Place a cherry in the center indention of each cookie.

In small saucepan combine chocolate pieces and sweetened condensed milk; heat over low heat until chocolate is melted. Stir in 1 tablespoon plus 1 teaspoon of the reserved cherry juice. Spoon about 1 teaspoon of the topping over each cherry, spreading to cover cherry. If frosting seems too thick, thin with a little more cherry juice.

Bake at 350° for 10 minutes, or until done. Remove to wire rack to cool.