1Heat oven to 375°F. In large bowl, stir cookie mix, butter, egg, 2 envelopes cocoa mix and 1 envelope marshmallows until stiff dough forms. Drop dough by slightly less than tablespoonfuls 2 inches apart on ungreased cookie sheet. Press marshmallows from remaining envelope on tops of dough.
2Bake 9 to 11 minutes or until edges are light golden brown. Cool 1 minute; remove from cookie sheet to cooling rack. Cool completely. Sprinkle with powdered sugar. Store tightly covered at room temperature up to 1 week, or freeze up to 3 months.