PREHEAT oven to 325° F.
COMBINE flour, cocoa, baking soda and salt in small bowl. Beat butter, granulated sugar, brown sugar and vanilla extract in large mixer bowl until creamy. Add eggs, one at a time, beating well after each addition. Gradually beat in flour mixture. Stir in 1 cup morsels. Drop by well-rounded tablespoon onto ungreased baking sheets. Top each dollop with 4 to 5 morsels.
BAKE for 11 to 13 minutes or until cookies are puffed and centers are set. Cool on baking sheets for 2 minutes; remove to wire racks to cool completely.