Hey Simon, a great drink! We had no Savoia and I substituted it with Angostura Amaro which also has strong vermouth-notes. However, I read that Sarah Morrissey used the sherry-based Atamán vermouth. So, I added 1 barspoon of medium sherry – and boom: the drink instantly became broader and deeper. Since Savoia is marsala-based, I wonder if a more sherry-esk note works better with the mezcal and the cacao.