For the chicken: Bring 8 cups of water, 1 bay leaf, ½ thinly sliced onion, 3 cloves of garlic and 1 tsp salt to a boil, then reduce heat, cover and simmer 10 minutes.
-Add 2 pounds skinless boneless chicken thighs and poach at a bare simmer, uncovered, skimming off any foam until just cooked through, about 20 minutes. Transfer chicken to a cutting board to cool.
-Pour broth through a fine-mesh sieve into a large bowl, discarding solids and reserving broth.
-When chicken is cool enough to handle, coarsely shred with your fingers.
To make sauce: Cook ½ cup hulled (green not roasted) pumpkin seeds in a small dry skillet over low heat, stirring occasionally until puffed about 6-7 minutes, the seeds will pop as they puff.
-Transfer to a bowl to cool then finely grind in a coffee/spice grinder or a blender.
-Take the husks off and wash 1# of tomatillos.
-Add them to a small saucepan with 1 cup of water and half an onion.
-Simmer covered until very tender, about 10 minutes.
-Drain tomatillos and puree in a blender with 2 fresh quartered jalapenos (seeds and all), ½ bunch chopped fresh cilantro, 1 tsp oregano, 3 cloves of chopped garlic and 1½ tsp salt.
-Heat 1 TBS butter in a 4-5 quart heavy pot over medium high heat.
-Then add puree (using caution as it will splatter and steam).
-Cook uncovered, stirring often until thickened, about 10 minutes.
-Stir in ground pumpkin seeds and 1 cup reserved broth and simmer 5 minutes.
-Stir in shredded chicken, 2-15 ounces cans of white hominy (rinsed and drained) and 3 more cups of the broth.
-Simmer partially covered for 20 minutes, then stir in ½ bunch of fresh chopped cilantro and serve in deep bowls with cubed avocado, shredded lettuce, chopped onion and lime wedges.