I'm keen to try Nigella's ginger biscuit tree decorations. How long are they safe to eat if they're on the tree? Also can I use gluten-free flour? Thank you.
Nigella's Edible Christmas Tree Decorations (from NIGELLA CHRISTMAS) are spiced cookies that can be decorated and hung on the Christmas tree. The cookies should last about a week once decorated, but this will partly depend on how heavily they are decorated and how humid the conditions are. The cookies soften over time as they absorb moisture from the icing and also from the air around them. If they are not too heavily iced and are hung in a cool, dry place then they should last around a week, but we suspect they will be eaten more quickly than this. We would also suggest that you use royal icing sugar or the egg white powder (meringue powder) mentioned in the introduction, to make the royal icing.
Unfortunately we haven't tried the cookies with gluten-free flour. Our concern would be that the cookies will be quite fragile, due to the lack of gluten, and this will make handling and hanging them much more difficult. Also you would need to make sure that the cookies are completely cold before you remove them from the baking sheet after baking.