Trout yogurt is an item in EarthBound. It can be obtained from Electra after giving her the Yogurt dispenser. It is a very fashionable treat for snobby, haute cuisine people in some big cities, like Fourside. It recovers 30 HP, and can be used with condiments. There is only one in the whole game.
In the Japanese Mother 2, this item is called Strawberry tofu. A different item also called Strawberry Tofu appears in Mother and Mother 3: In Mother, the player can give it to a professor and his assistants on an island that can be reached from a building near the Ellay harbor, and in turn, Ninten and co. can get Words of Love, Hate Words, and information about EVE; in Mother 3, Strawberry Tofu is simply a healing item.