In the first movie we can see Tai cooking something yellowish. Does someone knows what kind of food was he making?
2 Answers
You might actually be referring to the omuraisu (rice omelette) that Tai cooked for himself, his sister Kari, and Koromon in Digimon Adventure Episode 21, around the 8:38 mark. It's possible that you mistook that scene for being a part of the second part of Digimon: The Movie due to the fact that it takes place in the real world and has a similar washed-out color scheme.
Here's an album of relevant screenshots from that episode.
However, if you're actually referring to Digimon: The Movie, like Eric stated above in the comments, Tai cooks an egg in the first part of the movie, around the 7:33 mark. I don't believe there are any other scenes of him cooking anything else for the rest of Digimon: The Movie.
In the first movie Digimon Adventure Gekijouban (1999) the only food Taichi made is a fried egg.
In episode 21 of the first series he makes Omurice.