Combine the 5 pounds pork shoulder, 1 quartered onion, 5 garlic cloves, 2 bay leaves, 2 tablespoons kosher salt, and 1 tablespoon black peppercorns in a large stock pot. Fill stock pot with water, covering the pork by at least 2 inches.

Bring to a boil over high heat then reduce the heat to medium-low so it is gently simmering. Let simmer until the pork easily pulls apart with a fork, about 3-4 hours. Top off the water if it is starting to go below the level of the pork.

Meanwhile make the salsa: place a comal or large frying pan (ideally cast iron) over medium-high heat. Place the 2 pounds of tomatillos, the remaining 4 cloves garlic, the 2 jalapeños, and the remaining quartered onion on the comal. You may have to do this in batches depending on how large your comal is.

Cook the vegetables, turning frequently until they are evenly charred on all sides. The garlic will cook the fastest, remove it as soon as it is golden to prevent burning.

Remove the charred veggies to a blender (cut the stems off the jalapeños first). Add the cup of cilantro, the cup of water and the remaining 2 teaspoons salt. Blend until smooth.

Once the pork is tender, remove it from the broth to a baking sheet with tongs and let cool. Strain the pork broth and save it for making the tamales masa dough or another use like soup or beans.

Shred the pork into bite-sized pieces with your fingers, discarding any fat or gristle.

Place pork in a large bowl and pour half the tomatillo salsa over it. Stir to combine. If it needs more sauce add another cup or so. Save the remaining sauce to serve with the tamales. Taste the pork and season with more salt if needed.

Use the filling to make the tamales or transfer to an airtight container and refrigerate for up to 5 days or freeze for up to 6 months. Thaw in the refrigerator overnight before using. Filling makes enough for 2 dozen tamales.