from the Pernil recipe in Giving Thanks
1 large head of garlic, broken apart, and cloves peeled. (serious garlic lovers can use two heads)
1/4 c fresh oregano, or 1 1/2 T dried
2 t salt
2 t black peppercorns
3 T olive oil
1 5-6 lb bone-in, pork shoulder, untrimmed
The day before you will serve the roast, make a paste of the garlic, oregano, salt, peppercorns, and olive oil. (Mortar & pestle, blender, or food processor will work.)
Place the pork shoulder in a glass or ceramic roasting pan. Using a sharp knife, pierce the pork shoulder on all sides to a depth of 1/2 inch. Rub the entire shoulder with the garlic paste, making sure it gets into the guts. Cover the pan and roast with plastic wrap and refrigerate overnight, or for at least 8 hours.
You may also shove slices of garlic into the cuts. This is what I used the second head of garlic for.
Preheat oven to 450 before cooking.
Place the pan with the pork, fat-side up, on the middle rack of the oven. After 30 minutes, reduce the temperature to 300. Cook for an addition 3 to 3 1/2 hours, basting every 30 minutes with any pan juices. (You can add water to the pan by the half cup if needed.) THe pork should be tender when pierced with a fork, and the internal temperature of the roast should be 150. Remove the pork from the oven and allow to rest 15 to 20 minutes before carving.