Cut and ice brownies. To thin Chocolate Decorator Icing, heat in microwave at Defrost setting (30% power) for 20 to 30 seconds. Stir. Repeat until icing reaches pouring consistency.
Use third largest (3 1/4 in.) heart cutter to cut one brownie for each treat. Place brownies on cooling grid over parchment-covered pan. Cover cookies with thinned icing. Tap to smooth and let icing drizzle down sides. Let set, about 5 to 10 minutes.