Tiger! - Chartreuse is recessive to Russian - Black
Brittany hides Tiger! - Chartreuse, it was pulled by a Burmilla - Chocolate Silver Shaded, Brittany is a Tiger! Tiger! Collection starter. We already know its a new fur only available in the Tiger! Tiger! Collection starters so we aren't going to quibble over which cat hid it.
I played a hunch and paired her to a Siamese - Seal hiding Russian - Black or more recessive.
The resulting baby was a Russian - Black, since thats a traited fur we know that Brittany passed her hidden fur not her Genesis fur meaning the baby hides Tiger! - Chartreuse and that fur is therefore recessive to Russian - Black.