My filling, inspired by chef Alain Ducasse, had some lambs brain in it for a bit of extra flavor. If you want to add it, a half a lamb’s brain will do, or perhaps a bit of prosciutto or some pancetta.
Monégasque means of Monaco, and it appears that this is a variation of one of Monaco’s national dishes. A ravioli filled with chard, spinach, cheeses, and a bit of lamb’s brain (because why wouldn’t you?) is served on top of a stew of beef braised in red wine with carrots and herbs, very much like a Boeuf Bourguignon.