Parents of children at Bruntsfield Primary in Edinburgh were warned in a newsletter against supplying homemade cakes or baked goods for children's birthday parties due to fears over food allergies, although manufactured cakes are allowed.
Parents are now calling for the decision to be reversed and have found a supporter in the celebrity baker.
Hollywood, 47, said: "It is ridiculous home-made baked goods are not being allowed.
"Not only are these made at home with full knowledge of the ingredients going in, they are also often made with the pupil at home, thus teaching them many skills."
A council spokesman said schools take a common-sense approach as many pupils can have reactions to certain food ingredients.
He said: "Food purchased from shops comes clearly labelled which means the ingredients can be checked to ensure they are allergy free."