Cook the tomatillos until tender in salted water to cover, about 10 minutes. Drain the tomatillos and add to the pumpkin seeds, along with the green chile and onion. Remove 2 cups of broth from the posole pot and pour over the mixture. Scoop half the mixture into a blender and blend until smooth; if the mixture is too thick to move through the blades, add a little more broth to get it going again. Strain through a medium-mesh sieve, then repeat the puréeing and straining with the rest of the mixture.

Set a large skillet over medium-high heat and measure in the lard or oil. When hot enough to make a drop of the purée sizzle, add it all at once and stir constantly for about 7 minutes, until it has darkened some and thickened noticeably. Remove from the fire.

Remove the meat and bones from the pot and set aside to cool. Stir the pumpkin seed mixture into the pot. Let simmer for an hour, stirring frequently to ensure that nothing is sticking on the bottom.

While the soup is simmering, skin and bone the chicken and pork, removing all the fat. Discard the skin, bones and nasty bits. Shred the meat into large strands.

Fifteen minutes before serving, season the soup with salt (posole requires considerable salt) and add the shredded meat to the pot. Place the garnishes on the table in small dishes. Finally, dish up a large bowl of the posole and let everyone add garnishes according to their taste.