It is no different then Bishul, that putting it on the fire is all that counts, even though that it is being cooked at a later point in Shabbos, as long as you did it before Shabbos it is fine.
In addition to putting the uncooked food on the fire before Shabbos, doesn’t the cooking process have to be at least 50% completed before the onset of Shabbos? I’m only asking for clarification. This probably isn’t relevant to the main discussion here.