Step 1

Combine the onions, garlic, lime juice, 1 cup white wine, salt and pepper in the jar of a blender or food processor. Blend until smooth. If the mixture is too thick, add more wine. Reserve.

Step 2

Place the pork shoulder on a cutting board and score the skin with a sharp paring knife, making a cross-hatch pattern.

Step 3

Transfer the pork to a big bowl (or brining bag) and pour the marinade over it. Sprinkle with the herbs and rub the mixture into the pork, getting into every nook and cranny. Cover with plastic and refrigerate for 12 to 24 hours, turning a few times so every inch gets to soak the marinade.

Step 4

Preheat oven to 350 degrees F.

Step 5

Place the pork on a roasting pan and pour the marinade along with the remaining white wine.

Step 6

Roast for several hours, 35 - 40 minutes for every pound, turning every hour or so and adding more wine to the pan as needed, until the meat is very tender and a meat thermometer inserted in the thickest part reads 195-205 degrees F. Remove from oven.

Step 7

Turn the pernil skin side up, brush the skin with the butter and place it under the broiler until crisp.

Step 8

Let it rest, tented with foil, for at least 3 minutes (and up to 30 minutes) before serving with the pan juices.