The filling is insanely delish, except you can't really make out what it is other than butter and milk and cream and sugar. It's a spongy, tender, almost cheesecake-like substance. An examination of the ingredients confirms the theory - the top four ingredients matches our guestimates almost exactly.
This would really taste great with some green tea to wash down the intense flavor. But it doesn't get sickening like some other desserts. Try some, it's wack.
**** (4/5 stars)