Very nice mobile game! The idea is fantastic as well, I haven's seen a cooking game with similar mechanics and they worked quite well! One thing I think would help is if you make sure that the player doesn't get stuck with only big orders. Always having one or two smaller ones would make it a bit more interesting I think. As for future development, if you plan to continue working on the game, I'd suggest having some items/powers players could use in a pinch. Maybe being able to swap the places of two ingredients. But yeah, just some ideas.
Overall, I found the concept really interesting, great job! :)