1. Remove wrappers from chocolate pieces. Heat oven to 350°F.
2. Beat butter, granulated sugar, brown sugar and vanilla in large bowl until well blended. Add eggs and milk; beat well.
3. Stir together flour, cocoa, baking soda and salt; gradually add to butter mixture, beating until well blended. Stir in chocolate chips. Shape dough into 1-inch balls. Place on ungreased cookie sheet.
4. Bake 10 to 11 minutes or until set. Gently press chocolate piece in center of each cookie; remove from cookie sheet to wire rack. Cool completely. Makes about 48 cookies.
VARIATION: Omit cocoa; add an additional 1/3 cup all-purpose flour.