Heat oven to 350°F.

Place paper baking cup in each of 24 miniature muffin cups.

In large microwavable bowl, microwave butter, water and sugar uncovered on High about 1 minute or until butter is melted; stir until blended.

Stir in chocolate chips until melted.

Stir in vanilla and eggs until well mixed.

Stir in flour and baking powder.

Divide batter evenly among muffin cups, filling each with about 1 heaping tablespoon batter.

Bake 17 to 25 minutes or until set (do not overbake).

Lightly press 1 candy bar on top of each brownie cup.

Cool completely, about 30 minutes.