The day before you wish to make the pozole, cook the chicken. Combine all the
ingredients for the chicken and stock and bring to a simmer. Skim off any foam
that rises. Continue to skim for a few minutes, until there is no more foam,
then cover and simmer for 1 hour. Remove the chicken pieces and the bay leaf
from the broth and transfer the chicken to a bowl. Strain the broth through a
cheesecloth-lined strainer, cover; and refrigerate overnight. Allow the chicken
to cool until you can handle the meat, then remove the meat from the bones and
shred, discarding any fat. Transfer to a bowl, cover tightly, and
refrigerate overnight.
The next day, skim off and discard the fat from the top of the stock. Measure
out 2 quarts of stock and set aside. Freeze whatever remains.
Rinse the pozole and combine with the water. Bring to a boil, reduce the heat,
and simmer for 1 1/2 to 2 hours, until tender and the kernels have begun to
splay Drain over a bowl and measure out 1 quart of cooking liquid.
Meanwhile, prepare the tomatillo mixture. Simmer fresh tomatillos in water to
cover for 10 to 15 minutes, until tender. Drain and place in a blender (just
transfer the canned tomatillos to the blender). Add the sorrel, cilantro,and
chiles and blend until smooth.Heat the oil in a large heavy casserole or Dutch
oven over medium heat.