PREHEAT oven to 350° F. Lightly grease 12-cup muffin pan.
FOR BROWNIE BATTER:
STIR Brownie Mix, melted butter, egg and water in large bowl until well blended. Set aside.
FOR COOKIE DOUGH:
BEAT softened butter in large mixer bowl on MEDIUM-HIGH speed for about 2 minutes until creamy. Add Cookie Mix; mix on LOW speed for about 1 minute until small crumbs form. Add water; beat on LOW speed for about 1 minute until dough forms.
DIVIDE brownie batter evenly into prepared muffins cups. Drop cookie dough evenly by rounded tablespoons onto each cup of brownie batter.