Should've asked an expert*

LONDON, Dec. 14 (UPI) -- Tax officials have egg on their faces for failing to distinguish teacakes from biscuits -- potentially costing the British treasury $7 million.
In what was a crucial -- and possibly costly -- error, tax officials for years insisted that a Marks & Spencer chocolate teacake was really a biscuit -- what the United States calls a cookie -- the Times of London reported Friday. Biscuits and teacakes are taxed at different rates; teacakes at a higher rate.
Twenty years later, tax officials admitted their error and said the teacakes were really biscuits after all. And Marks & Spencer wants its overpayment back.

Teacakes a taxing topic for department - UPI.com

*Expert advice on cakes here