Step 1Cut off the top half of the head of garlic so that the cloves are exposed. Quarter the onion. Cut the pork into 3-inch cubes. Place the pork in a large pot with the bone, if there is one, along with the cut head of garlic and the onion. Add salt to taste and enough water to cover. Bring the water to boil and simmer the pork, covered, for at least 4 hours. Refrigerate the pork overnight, covered.
Step 2The next day, remove the fat, gristle and the bone, and shred and save the cooked pork. Strain and save the broth to make the mole sauce.
Step 1Simmer the California and New Mexico chiles in water for 10 minutes to soften them. (Beware the fumes from the cooking chiles.) Cool the chiles. Remove and discard the stems, seeds and veins.
Step 2Toast the pumpkin seeds and sesame seeds in a skillet over medium heat until golden, about 6 to 8 minutes.
Step 3Remove the papery skin from the tomatillos and simmer the tomatillos in the reserved pork broth until tender, about 20 minutes. Drain the tomatillos and set aside, reserving the broth.
Step 4Cook the onion in the oil over medium heat until tender, about 6 to 8 minutes. Set it aside.
Step 5In a blender, combine the seeded chiles, toasted pumpkin and sesame seeds, tomatillos, onion, garlic, salt to taste, cumin and 2/3 cup reserved pork broth. Blend together, then pour the mixture through a sieve, saving the liquid. Return the solids to the blender, along with another 2/3 cup pork broth, and blend again. Pour the mixture through the sieve again, discarding the solids and placing the sauce in a saucepan.
Step 6Simmer the mole sauce for 30 minutes. Combine the sauce with the reserved shredded pork and set it aside to cool. The filling should not be runny.
Step 1In the bowl of mixer, combine the masa with the baking powder, about 3 tablespoons of pork broth and the melted lard to "lighten" the masa. Beat together, then test the consistency by breaking off a small piece of masa and trying to float it in water. It is not absolutely necessary that it float, but a light, spongy consistency of the masa is critical to good tamales. The masa can't be beaten too much.
Step 1Soak the hojas in hot water to soften, about 20 minutes. Sort out the smaller pieces and discard. Drain the large hojas just before filling.
Step 2Take a large hoja and dry it with a paper towel. Hold the hoja in one hand and spread about 2 tablespoons of masa over the hoja with the back of a spoon, or lay the hoja flat on a table to spread the masa. Place about 2 tablespoons of the pork-mole filling on the masa. Fold over the hoja from the side. Now fold over the opposite side to seal the masa. Fold up the bottom of the hoja. The tamale is ready for steaming. Repeat the process with the remaining tamales. (The tamales may be frozen at this point for steaming later.) If necessary the folded tamale may be tied with a strip of hoja to hold it together.
Step 3Stand the tamales open-end up in a steamer. You may need to steam them in two batches. Steam the tamales until the masa is cooked and firm, 35 to 45 minutes. Repeat with the remaining tamales.