Ice smooth 2-layer cake (bake two 1 1/2 in. high layers to make a 3 in. high cake). Tint 8 oz. fondant dark rose, 6 oz. light rose and a 1 1/2 in. ball light green; reserve remainder white. Roll out light rose fondant 1/8 in. thick; cut two 1 x 15 in. long strips. Position strips flat around top border of cake; trim to fit heart shape.