Preheat oven to 300°F.
In a very large Dutch oven or roasting pan, layer pork, oranges, lemon, garlic, bay leaves, and salt. Pour in oil until the pork is mostly covered (don't worry if a few pieces peek out).
Cover tightly with a lid or heavy foil. Cook for 3.5-4 hours, until the pork is very tender and shreds easily with a fork. (Check around the 3 hour mark.)
When done, use a slotted spoon to transfer pork and citrus to a foil-lined sheet pan. Spoon some of the cooking juices over the top. Yes, you'll eat the oranges/rinds- it's not bitter after that long cook.
Sprinkle evenly with brown sugar (start with 1 ½ cups, add more if you like it sweeter).
Place under broiler until sugar caramelizes and pork crisps, about 5–8 minutes. Watch closely — it can go from caramelized to burnt fast!
Serve hot with warm tortillas and toppings of your choice- I like refried beans, guacamole, pico de Gallo, and some queso fresco.
