"I just laughed. I thought it was so stupid."
Her cake was made with standard ingredients including flour and free-range eggs.
She said she could not understand why a bought cake should be any safer than a home-made one.
She said: "When I compared the recipe to the shop cake, that was full of artificial dyes and all sorts of things, which made it even more ridiculous."
Age Concern said many of the guests at the private club had special health needs and the priority was to look after them.
It said its decision was not a reflection on Mrs Richards' cooking.
Regional director Andrea Scott said: "The average age of residents is 85, they have many disabilities and some of them are diabetic and our policy is to keep them as well and safe as possible.
"We are just trying to be responsible and bought cake is a responsible line we have adopted."
