And they are also poisonous...

In 2004, healthcare professionals warned against overindulgence in Pontefract cake after a 56-year-old woman was admitted to hospital following an overdose. The woman consumed about 200 grams (7.1 oz) daily, leading to dangerously low potassium levels and subsequent muscle failure.

https://en.wikipedia.org/wiki/Pontefract_cake

At that dosage, this "sweet" is one of those things that must be locked away if there are any kids/dogs in the house.