Cut the 3-4 pounds of boneless pork butt into 6 or 7 large pieces. Combine 1 tablespoon kosher salt, 1/2 teaspoon freshly ground black pepper, 2 crushed bay leaves and 1 teaspoon dried Mexican oregano in a small bowl then sprinkle over the pork on all sides, using all the seasoning mixture. This step is best done 1 or even 2 days in advance. Leave uncovered in the refrigerator until ready to use.
When you are ready to cook, remove pork from the refrigerator 1 hour in advance. Heat 1/4 cup lard (or vegetable oil, if using) in a large, heavy-bottomed pot over medium-high heat. Add pork (in batches if necessary, don't crowd the pan) and brown pork on all sides, about 5-8 minutes per side.
Add remaining ingredients to the pot, then add enough water to cover three-quarters of the way up the side of the pork. Bring to a boil, then reduce heat to a simmer. Cook, uncovered, turning occasionally until pork is pierced easily with a fork, about 3 hours.
Remove pork from pot. When pork is cool enough to touch, shred or cut into bite-sized pieces. Return pork to pot and raise the heat to medium-high. Continue cooking until almost all the liquid has evaporated and all that is left is the rendered fat. Turn the heat to low and fry meat, stirring frequently until edges are crispy and well-browned.
Serve in warm tortillas with minced white onions and your favorite salsa.
