Like the conveyor toasting machines you see at buffets, raw beef goes in steak comes out Google images

This could be nice to be multiblock, but not conventional - more of a long line of these conveyor ovens that 'connect' together LINK
The raw beef would have to go through say two of these blocks to be cooked on the other end, iron dust would have to go through say 5 of these conveyor ovens (ofc in iron ingot cast basin goes in but we can overlook that) so you can determine the process time of the ovens via how many it requires to cook the item.

Optional extra - if you say placed raw beef through 5 conveyor ovens instead of 2, it burns the item - either make burnt items of all the meat or one 'ash' item that they all turn into..
This would make it so that you dont have one oven for all things, and I think would be much more realistic (not that ores are processed in this way irl)

Sorry about the thought process being written down with this one - is still late at night

turbo furnace added instead