Now that I had the chance to look up the official rules once more, I say it is pretty clear:
The game ends when one or more players have no batches left.
Between all chefs with no batches left, the winner is the chef with the most ingredients in hand.
In case of a tie:
If the chef who ended the game is involved, that chef is the winner! Otherwise the game is a draw.
So in your scenario the winner is definitely the sole player that ended the game with NO BATCH left, no matter if he/she has ingredients in hand or not.