Prepared meals are immensely valuable and infinite in supply. Steel is not. Therefore, I prefer prepared meals as a trade good.
I agree in the long term that exporting prepard meals would be the berst course of action but since I don't get a food industry setup (as in prepared food) large steel serrated discs will be my choice for the first year becasue you need a steel industry to survive the ork onslaught in Masterwork mod any way.
When I play Fortress Defense, often the first industry I set up is prepared meals. Much later on, I sell totems and invader clothing with sewn images.
First off, you only need one weapon and armor smith to make all your weapons and armor. They can easily be the same person. If you use traps, that's a mechanic, but he only needs to be free for as long as it takes to set up the traps. If you have multiple weapon and armor smiths who all work, you are distributing experience over many individuals, decreasing the quality of produced items and wasting experience. Specializing arms and armor production frees up someone who specializes in food.
Second, you need someone to handle farming, and you can easily overproduce easy food like plump helmets. This makes it easy to have farming labor left over that can be used to grow cave wheat or quarry bushes; the latter produce extraordinarily large stacks of food, and it can still be eaten by your dwarves while also giving them happy thoughts.
Thirdly, even a few of the prepared meals (lavish meals of course) created by an absolute novice can buy out a caravan. No need to train someone up for ages to turn an excellent profit.
Fourthly, if you need all that steel to defend yourself, why are you selling it? If you have any non-masterwork steel items currently in use in a trap or by your militia, each additional bar of steel is best used trying to replace that item rather than being traded to the traders. At the same time, if you are being pushed to the margins to defend yourself against tough early invasions, then surely you would be better off employing the steel discs in weapon traps to guarantee survival or giving extra steel weapons to back-up militia in case your main squads perish?