Prepare brownies according to box directions. Allow to cool.

Remove from pan and cut as many heart shapes as possible with cookie cutter.

Puree raspberries in food processor or blender.

In a medium bowl, cream butter and raspberry puree.

Add in powdered sugar 1 cup at a time. Mixing until smooth and creamy.

Transfer filling to piping bag.

Pipe filling around the edge of one of the brownie hearts. Then fill in the middle. Top with another brownie heart, gently pressing down to make a sandwich.

For the finishing touch, dust the tops with powdered sugar.