Itami is a biased judge, his verdict is invalid... I know the joke, but i think Tuka is the winner by the sheer care and technique she put in her dish, sure... Rori "made" a roast with a extremely rare cut of choice meat, but... well, it was more Yao's effort (curious what that fire spirit thought of being used to roast meat for a whole night).
Continue about Yao... imagine being able to control flames so that it slow roasts perfectly evenly a huge chunk of high-quality meat? Man, that is a dream.