Daddy Eddie'S Roast Pork (Pernil), Puerto Rican-Style - cooking recipe

Ingredients

1/4 cup olive oil
3 tablespoons white vinegar
10 cloves garlic, or more to taste
2 tablespoons dried oregano
1 tablespoon salt
1 1/2 teaspoons ground black pepper
5 pounds pork shoulder, trimmed of excess fat

Preparation

Combine olive oil, vinegar, garlic, oregano, salt, and black pepper in a mortar and pestle; mash into a paste.
Make deep slits into the pork with a small knife. Stuff slits with the paste; rub any remaining paste over the pork.
Place pork in a plastic roasting bag and put in a roasting pan with a rack. Let marinate in the refrigerator, 8 to 48 hours.
Take pork out of the refrigerator, uncover, and bring to room temperature, 1 to 2 hours.
Preheat oven to 300 degrees F (150 degrees C).
Roast pork skin-side down in the preheated oven until golden brown, about 2 hours. Flip pork and continue roasting, skin-side up, until juices run clear and an instant-read thermometer inserted into the center reads at least 145 degrees F (63 degrees C), 2 to 4 hours more.