HEAT oven to 350°F. Beat brownie mix, melted butter, cream cheese and egg in medium bowl 50 strokes with spoon until well blended (dough will be sticky)
. DROP dough by rounded tablespoonfuls 2 inches apart onto ungreased cookie sheets to make 24 cookies; smooth edge of each to form round cookie.
MIX powdered sugar and peanut butter in small bowl with spoon until mixture forms a ball. With hands, roll rounded teaspoonfuls peanut butter mixture into 24 balls. Lightly press 1 ball into center of each ball of dough.
. BAKE 10 to 14 minutes or until edges are set. Cool on cookie sheets at least 30 minutes
. SPREAD thin layer of frosting over peanut butter portion of each cooled cookie.