A classic Lechon Asado, a citrusy garlicky pork roast slowly cooked to slice or cooked a bit longer for pulling.
Shoulder & Sauce:
Add peppercorns to food processor and pulse to break down. Add garlic, salt, dried oregano, onion, and pulse again. Slowly, through the feed, add the sour orange juice until mixed thoroughly. The mixture should not be completely smooth.
Heat the olive oil in a saucepan until warm, remove from heat and carefully add the mash and zest to it. Whisk to combine and let cool. Place a half a cup of it in the refrigerator.
Shoulder & Sauce:
Pierce the pork all over, multiple times with a very sharp knife, working it in fairly deeply. Ready a roasting dish, just a bit larger than the pork, line with a generous amount of plastic, hanging over the edges. (Enough to wrap the pork in) and place the pork on top.
Pour the garlic mixture all over the pork, rubbing it into the cuts and crevices. Pull the plastic up over the sides and top, sealing the marinade tightly to the pork. Refrigerate for a minimum two to three hours, but overnight is definitely preferable.
When ready to cook, remove the roast about 30 minutes beforehand, preheat oven to 450 degrees. Remove plastic and scoop as much of the marinade as possible up and over the pork. Place in oven, turn down to 325 degrees and cook for about 4 1/2 hours for a tender roast (temperature should register at 170 to 175 degrees) or longer for a pulled roast (temperature should be at about 195.)
Baste roast occasionally with the juices, and watch the liquid level at the bottom of the pan. Add water if necessary, and it is likely it will be – do not let the juices dry and burn.
Remove from oven, tent lightly with foil and let rest for 20 to 25 minutes. Place the juices in a saucepan, defat if desired (strain & save the fat if making bread for Cuban sandwiches) and heat the juices in a small saucepan over medium-high. Add in onion and cook for several minutes until the onion is tender. Add the reserved Mojo and cook for a just moment or two longer to take off the raw garlic taste. Taste and adjust seasoning, adding salt and pepper if needed.
Pour a little of the sauce over the sliced or shredded pork and pass the rest.
Allow 1/4 to 1/2 pound per person.