Pokémon - Season 10 Episode 24 Cooking Up a Sweet Story! Gotta catch 'em all!
Overview: When a girl named Theresa asks Ash to let Pikachu stand in for her aunt Abigail's lost Pikachu, Sugar, to help her win a baking competition, the ruse seems to work, until Abigail challenges Ash to a Pokémon battle against Pikachu. Will Ash be able to battle his own partner and best friend.