Preheat oven to 375°. In a large bowl, cream butter and sugars until light and fluffy, 5-7 minutes. Beat in eggs and vanilla. In another bowl, whisk flour, cocoa mix, baking cocoa, salt, baking soda and baking powder; gradually beat into creamed mixture. Gently stir in marshmallow bits and chocolate chips., Drop dough by tablespoonfuls 2 in. apart onto greased baking sheets. Bake until set, 10-12 minutes. Remove to wire racks to cool completely.