Sea-salt ice cream

Sea-salt ice cream (シーソルトアイス) is a type of ice cream found in Twilight Town and Radiant Garden. It appears throughout the Kingdom Hearts universe, but made its first appearance in Kingdom Hearts II. Kingdom Hearts II is also the only game in which the ice cream features as an attainable key item. The ice cream's flavor mixes both a salty taste and a sweet taste.

An interview with Tetsuya Nomura after Kingdom Hearts II explained that Nomura first tasted sea-salt ice cream at a trip to, a smaller resort of Disney's parks in Japan. He liked the ice cream very much and decided to work with Disney to have it put into Kingdom Hearts II. He also said that the idea to put the dessert into the game came to him when he was thinking about what the kids in Twilight Town do and eat over summer vacation.

Kingdom Hearts Birth by Sleep
Following Terra-Xehanort's defeat and their subsequent ejections from Hollow Bastion, Lea buys two sea-salt ice creams from Scrooge McDuck and gives the other ice cream to Isa.

Blank Points
After Terra-Xehanort is taken in as an apprentice, Ansem the Wise and Ienzo eat sea-salt ice cream together while walking down a hall of the castle in Radiant Garden. Axel, Roxas, and Xion are also seen eating sea-salt ice cream together in Twilight Town as they had during their days in the Organization. Roxas and Xion then say Sora's name in unison.

Kingdom Hearts Re:Chain of Memories
During the end credits, Roxas passes Hayner, Pence, and Olette in Twilight Town. The trio each has their own bar of sea-salt ice cream. He later eats his own along with Axel on top the clock tower.

Kingdom Hearts 358/2 Days
In Kingdom Hearts 358/2 Days, sea-salt ice cream is a recurring element in the game's plot and the system icon that is seen upon the initial startup of a Nintendo DS.

Axel treated Roxas to sea-salt ice cream on the Twilight Town Clock Tower, saying it was "icing on the cake", after Roxas completed his first mission and reminding him they sat there the first day Roxas got his new name. He then suggested that he and Roxas should meet each other to eat ice cream every day after they completed their missions, stating going back and forth to the Castle That Never Was was boring. After Axel left for his mission in Castle Oblivion, Roxas invited Xion to join him. Soon Roxas, Axel, and Xion began eating ice cream together after their missions. Sea-salt ice cream is Axel's favorite flavor.

During a day in the game, named "Vacation", Roxas had no idea on what to do. After rejecting Xion's offer of practicing with the Keyblade, he once again looked at the notice posted in the Grey Room. While looking at the notice that said "Operations Closed for Vacation", Roxas thought, "What to do? What to do?". Then he concluded the scenario saying the word "Ice cream". This perhaps shows that Roxas had learned to like ice cream ever since Axel had given him one.

It is revealed in the game that some ice cream sticks have the word "WINNER" on it, "あたり" in the Japanese release. This allows the owner to get a free ice cream bar. Axel first notifies Roxas of this on one of their later meetings, after Roxas found a WINNER stick, but kept it secret. He later bestows the stick to Axel as a farewell gift when he leaves Organization XIII.

It also acts as a symbol of the friendship between the three of them, most notable when Roxas asks Xion who he'll eat ice cream with as she vanishes.

Kingdom Hearts II
Hayner, Pence, and Olette also enjoy this ice cream. The three of them often enjoyed eating it together. When DiZ created the Simulated Twilight Town, he made data versions of them to be friends with Roxas and they often ate it. In one of Roxas's flashbacks, Axel offers him a stick of sea-salt ice cream before their parting.

After Riku steals the digital Olette's Munny Pouch from Roxas, he asks DiZ what to do with it, and DiZ jokes, "We could always buy some sea-salt ice cream."

When Sora arrives in Hollow Bastion, he sees Scrooge McDuck, who is trying to recreate the recipe for sea-salt ice cream. Through subsequent visits as the storyline advances, Scrooge comes closer to reinventing the flavor and ultimately succeeds.

Riku left a sea-salt ice cream with a picture of Roxas and the gang from the Simulated Twilight Town as clues for Sora, Donald, and Goofy. Donald took an immediate liking to the ice-cream, and Sora is quoted in his second visit to Twilight Town saying "Donald ate it up."

It was shown in the game that Ansem the Wise was very fond of this ice cream, and often ate it while conversing with King Mickey, sharing it with Ienzo and later used it as the password for his computer in the Old Mansion, which Sora, Donald, Goofy, and Mickey use to enter the Simulated Twilight Town.

In the Kingdom Hearts II manga, Roxas falls off the Clock Tower while trying to catch his ice cream that was sliding off of the stick. If you look closely, the ice cream stick had "WINNER" imprinted on it.

In the main menu, Sora is seen to have had sea-salt ice cream as well, since the stick is hanging from his mouth.

Kingdom Hearts 3D: Dream Drop Distance
Axel and Roxas eat sea-salt ice cream in Lea's dream just before his awakening.

As the secret message is spelled out during the end credits, Lea is seen eating sea-salt ice cream while sitting atop a capital "N".

Trivia

 * In Kingdom Hearts II, the sea-salt ice cream appears in the inventory screen, even though Sora said Donald ate it.