Hypothetical: Do you lose anything by pre-cutting pork shoulder roast?
So let's say I have a whole 4-lb pork shoulder, seasoned, seared, and ready for the oven. Let's say it takes 3 hours at 400 degrees F to roast through to a nice, pullable 190 degrees and develop a good bark on the outside.
Now, what do we gain and/or lose by cutting this shoulder roast in half and roasting at the same 400 degrees? If we make sure to finish at the same internal temp of 190, It seems to me like we have would a significant roasting time reduction plus more crusty bark, with no downside that I can think of.
In fact what if we keep cutting and cutting until we have basically pre-pulled the raw shoulder before roasting? Would this result in maximum bark and minimum cooking time?
Worth experimenting. I do have some expectations, though. It would work pretty well to cook the two halves, and you would in fact stand to get more bark, but then also proportionately less of the interior juicy part. So you'd probably find the balance shifted slightly.
But I expect that precutting into small chunks or prepulling would not be good, because there would be too little meat structure left to hang onto the melting fats and collagens that leave the meat unctuous and juicy for pulling. If you cook smaller parts largely immersed in a fluid, however, then you are making a pork stew/chili, which keeps that good stuff in play. Yum!
Depends on how you cut it. The main determinant of cooking time is thickness rather than weight, so if you cut in such a way that the thickness is halved, the cooking time would be significantly lower to reach 190. The meat will also tend to be a little dryer and less tender, since breaking down collagen into gelatin is a function not only of internal temperature but also of time. And incidentally, you might not make the deeply crisped crust you're used to - more below.
If you cut in such a way that the thickness of the two pieces is the same as the thickness of the original big piece, they would still take almost 3 hours to cook. You would have more surface area, which might lower the cooking time a bit, and also yield more crusty bark.
"In fact what if we keep cutting and cutting until we have basically pre-pulled the raw shoulder before roasting? Would this result in maximum bark and minimum cooking time?"
Sort of. I've seen techniques where fully braised (or otherwise slow-cooked) meats are pulled apart and then recooked to make all of the meat crispy and crusty. If you cut the meat into small enough pieces, you could essentially cook it until it's all crust. But there are a couple issues - for one, sitting directly on the pan makes meat crisp up a little differently than the outer surface of a chunk of meat with nothing but air cooking it. The cooking can be uneven and you'll have a greater tendency to burn some of the meat. Also, your cooking time probably won't be as low as you think. The crust you form on a 3 hour roast is what the surface of the meat looks like after 3 hours at 400 degrees. It takes 3 hours NOT ONLY to cook the center of the meat through to ~190, but also for the crusty bark to form the way you like it. A less-thick hunk of meat will cook faster, but won't really form a bark any faster.
Sometimes I will take a 7-8 pound butt, cut it up into 2" chunks and roast them in the oven. It obviously doesn't take as long to cook as the whole roast and yields succulent meat that is useful for many different further preparations. It still takes a good while to get it cooked to the falling apart stage.
Edit: doing it the way I've described does not really result in any bark as I would define it.
This is partially correct.
Braising will dry the meat out faster than will smoking or roasting it. Braising only keeps the outer most layers of meat moist during cooking, but will dry the meat out just the same or faster than an equivalent temperature dry heat method.
What keeping it one mass does do is help the balancing act between not having the outside completely dry out before the inside has had a chance for its connective tissues to dissolve (i.e. collagen to convert to gelatin). Cutting the shoulder down into smaller and smaller pieces greatly increases the surface-to-mass ratio thus skewing the balancing act previously mentioned from quite a bit to severely depending on how many times the shoulder is cut. If the cutting is taken to the extreme, then the inside runs the risk of drying out as well before the connective tissues have a chance to break down.
I have gotten pre-sliced pernils at Spanish markets before and found that they cooked up just fine braised in a dutch oven (i.e., in a pot roast style). I never tried rack-roasting the sliced pernil and can't imagine it would be very successful, but I don't know from personal experience of course. The big improvement was that the marinade permeated the meat faster and more thoroughly.