Depends on which game. If it's the first one, you need to synthesize everything else in order to get the Ultima Weapon. If it's in the second one, you need to go to Twilight Town and enter the room with the pods. It's in a chest.
Ultimate Recipe Showdown - 2008 Desserts 2-5 was released on: USA: 8 February 2009
Ultimate Recipe Showdown - 2008 Burgers 1-2 was released on: USA: 24 February 2008
Ultimate Recipe Showdown - 2008 Burgers 2-2 was released on: USA: 11 January 2009
Ultimate Recipe Showdown - 2008 Burgers 3-4 was released on: USA: 4 April 2010
Ultimate Recipe Showdown - 2008 Cakes 1-4 was released on: USA: 9 March 2008
Ultimate Recipe Showdown - 2008 Cakes 2-3 was released on: USA: 18 January 2009
Ultimate Recipe Showdown - 2008 Cookies 1-6 was released on: USA: 23 March 2008
Ultimate Recipe Showdown - 2008 Hometown Favorites - 2.6 was released on: USA: 22 February 2009
once you beat the game, go to the basement of the old mansion in twilight town. The normal one, not the cloned one. there will be a chest in the basement hall with the ultima recipe in it. go to a moogle and you can synthesize it if you have the right ingredients. Otherwise....... do what i did and use cheats!
In kingdom Hearts 1, the best Keyblade is Oblivion, obtained in Hollow Bastion. In KH2, you have to synthesize it.
Ultimate Recipe Showdown - 2008 Comfort Foods 2-1 was released on: USA: 4 January 2009
Ultimate Recipe Showdown - 2008 Hometown Favorites 2-6 was released on: USA: 22 February 2009