Has anyone beaten this HoS boss on NG+ deathmarch?

The painting ghost? It seems impossible to beat her on ng+ dm or even blood and broken bones, she fully heals without even being near a panting when it comes alive within seconds. I can stay alive fine but after 20 min I just turned it down to normal.
The only way I imagine to beat her on ng+ dm would be with an OP super dps build and just burning her down before she can heal at all.