PureCacao

PureCacao is the slash ship between Dark Cacao Cookie and Pure Vanilla Cookie from the Cookie Run fandom.

Canon
The two are seen fighting Dark Enchantress Cookie in the Prologue. Alongside them are, with Golden Cheese Cookie, HollyBerry Cookie, and White Lily Cookie. In addition, they interact several times during the game mode Cookie Odyssey. They also have good lore in the Official Cookie Run artbook. They are shown to be good friends, and, the letter that Pure Vanilla sent him in Ep. 14 implies they used to spend time with one another before the Darkness came.

Since they are battle mates, most of their official artwork is of the two—often also including HollyBerry Cookie—sitting together in a sort of renunion.

Pure Vanilla Cookie's Letter
"Dear Dark Cacao Cookie. How have you been? Is the pure white sugar snow falling over there as it always used to? I'm writing this letter in front of a cozy, crackling bonfire with a nice cup of fragrant vanilla tea. It's such a warm and comforting place. Yet, for the longest time, I was trapped in a void.

It was darker than the darkest night, and colder than the harshest winter. But then I was saved by a group of Cookie travelers. Their pure, crispy hearts helped me find my smile again. We laughed, feasted on sweets together, and exchanged pleasant stories. They reminded me of us during our own adventures. Dark Cacao Cookie. The great Shadow is once again hanging over our world. We, Cookies, value our freedom above everything else, but it is time to stand up and fight against forces trying to take that freedom away.

We still have our Soul Jam. The lights still hasn't faded, and neither has our courage nor will. Perhaps, the sole reason we are even here is because we still have our mission ahead of us. Don't you agree? I believe that it is our path to follow, so that other Cookies, young and curious, have a chance tp see the wide world that is out there, as we saw it in the past. So let us turn our vision towards the future. For the good of all Cookies, and... for you and me. I wish to meet you again. With respect and love, Pure Vanilla Cookie. (PS. I was busy writing the letter I forgot to feed the birds! I think I'll have to play with them some extra to make them happy again.)"

Fanon
is a passably popular ship in it's fandom—though some fans may deny it—and has a notable amount of followers. This ship is mainly popular because of the content in the Official Artbook. It is also because of Pure Vanilla Cookie's letter. And suprisingly, from the few interactions they hold during the Cookie Odyssey. However, they were still shipped even before Dark Cacao Cookie was released on February 24, 2022. They currently have 120+ works on A03. They also have 89 stories on Wattpad.

On AO3 and Wattpad, PureCacao stories use many Tropes such as, "Glad to Be Alive" Sex, Battle Couple, Childhood Friend Romance/Childhood Marriage Promise, First Kiss, Long-Distance Relationship, Love Across Battlelines, Secret Relationship, You Are Worth Hell, etc...

This ship is rivaled by the main ships: CacaoLily and PureLily. It is also rivaled by ships including Cacao Cookie, and ships including Pure Vanilla Cookie.

Trivia

 * PureCacao has the second most fanfictions written on Ao3, with 184+ stories.
 * Cookie Run's Twitter account has past activity of looking at PureCacao posts and liking them.
 * in the video "We made our Voice Actors React to YOUR Fan Art" made by the official YouTube account for Cookie Run Kingdom, Dark Cacaos voice actor is seen reacting to Pure Cacao content, without a single clue what it actually was.