Epicurian. com. I only had a little over a pound of pork loin so I halved it. The proportions and instruction according to the site are as follows: (my notes are in blue)
2-1/2 lb. fresh pork loin
12 garlic cloves peeled and crushed
1 large onion chopped
1/2 cup sour orange juice (or 1/4 cup unsweetened orange juice & 1/4 cup lime juice)
2 cups water
1 cup pure Spanish olive oil
1/2 teaspoon salt
1/2 fresh onion sliced into rings
1 teaspoon oregano
1 teaspoon cumin
Cut pork into 2 inch chunks. To prepare marinade: mix together garlic, chopped onion, orange juice, 1/2 cup olive oil, oregano, cumin and salt. Pour over pork chunks and marinate for at least 3 hours or overnight in the refrigerator.
Remove meat from marinade. Place in pot with two cups of water and 1/2 cup olive oil. (I did not remove the meat from the marinade; I placed all of it in the pot) Simmer, uncovered until all water boils away -- about 30 to 45 minutes. (The pork became very tender during this process.) Brown the pork in the oil until crispy on the outside. Add onion slices and saute briefly. Garnish with lime wedges. (I skipped these last two directions since I placed the pork in the pot with the chopped onions from the marinade and it already had lime juice).
Tip from Maria: If in the end your masitas are pale in color, you can quick-fry them in a non-stick skillet with some olive oil on high (for a couple of minutes).