Shokugeki no Soma X Isobe Isobee Monogatari is a crossover made by the manga artists Shun Saeki, the illustrator of Shokugeki no Soma and Ryō Nakama, the creator of Isobe Isobee Monogatari. The extra retells the first few chapters of the Shokugeki no Soma manga with minor alterations in the storyline, mostly for comedy.
Sōma has finished cooking Grilled Squid Tentacles Dressed in Peanut Butter and ends up with a reaction that annoys Erina Nakiri. To apologize Sōma for the act, Erina tells Sōma to cook an egg dish. Since Sōma is not paying attention to Erina, he asked if any dish was fine like Noriben and Erina replied saying she needs a dish with eggs. He then proceeds to making Transforming Furikake Gohan.
While making the gohan, Hisako and Erina are criticizing Sōma's acts while cooking as he was an unexperienced cook. Erina wondered what he was cooking and Sōma reacted by laughing and saying that she did not know what he is cooking after watching from a distance. When Sōma served the dish, it was censored. Erina immediately rejected the dish but Sōma immediately countered by placing the soup stock into the dish. Erina then tastes the dish, then tries to stop taking another bite. Meanwhile, Hisako reacts that all of them cannot explain the dish well without Morisaki's help. A reaction came with a half-naked Erina telling the illusions of Sōma to go away from her. Soma then tells his catchphrase with a twist, saying "It wasn't much... in more ways than one!"
He is then given thanks by the members of the Polar Star Dormitory. In the end of the extra, Sōma says he gained the experience of failing. Jōichirō also appears in the last frame, telling Sōma to catch up and follow him.