1) Heat oven to 350F.
2) Prepare brownie batter as directed on package. Spoon into 20 paper-lined muffin cups.
3) Beat cream cheese, sugar, egg, peanut butter, and vanilla with mixer until blended. Spoon 1 rounded tablespoon into center of batter in each cup, pressing down slightly into batter. Bake 30 minutes or until centers are set.
4) Serve topped with Cool Whip and cherries.