FoodSweet
Bertie Bott's Every Flavour Beans
Bertie Bott’s Every Flavour Beans are wizard sweets that really do mean every flavour, including the unpleasant ones. They are sold on the Hogwarts Express trolley. Dumbledore later recalls being put off them by a vomit-flavoured bean in his youth.

First mention
Harry Potter and the Philosopher's StoneChapter: The Journey from Platform Nine and Three-Quarters
Harry buys a box from the trolley on his first train ride and shares the risk with Ron.