Who said atom is like a raisin bun?

The idea that an atom is like a raisin bun was proposed by physicist J.J. Thomson in his "plum pudding model" of the atom in 1904. He suggested that atoms consist of a positively charged "batter" with negatively charged electrons (the "raisins") embedded throughout. This model was an early attempt to describe the structure of the atom before the discovery of the nucleus.