Season the chicken all over with salt and pepper. Bring the chicken stock to a boil in a large saucepan. Place the breasts in the stock, reduce the heat to moderate, cover and cook until the meat is tender, about 15 minutes. Set aside to cool in the stock. When cool, remove the skin and bones and shred the meat into bite-sized pieces. Strain and reserve the stock for another use.
In a large mixing bowl, combine the fresh tomatillo salsa, heavy cream, 1 teaspoon salt, 1/2 teaspoon pepper, the onion and shredded chicken pieces.
Heat the vegetable oil in a medium skillet over medium-low heat. Cook the tortillas just about 5 seconds per side to soften, and then transfer to a large colander to drain.
Preheat the oven to 350 degrees F. Butter a 4 quart casserole or 6 to 8 individual casseroles (at the restaurant, we use small soup bowls).
Combine the cheeses in a mixing bowl.
To assemble the chilaquiles, spread a thin layer of the cheese mixture over the bottom of the baking dish. Push the solids in the bowl of chicken and tomatillo sauce to the side so the liquids form a pool in the bottom. Dip all the softened tortillas in the pool to moisten. Layer one third of the moist tortillas over the cheese and top with half of the chicken mixture with its sauce. Sprinkle half of the remaining cheese over the chicken. Repeat the layers, ending with a layer of tortillas on top. Cover tightly with aluminum foil.
Bake 30 minutes or until the edges are slightly brown. Let sit for 10 minutes before slicing and serving or unmolding.
In blender place tomatillos, jalapenos and water. Puree until just chunky. Add remaining ingredients and puree about 2 minutes more, or until no large chunks remain. This salsa keeps in the refrigerator, in a covered container, about 3 days.
In large bowl combine all ingredients and stir until smooth. The dough should be slightly sticky and form a ball when pressed together. To test, flatten a small piece of dough between your palms. If the edges crack, add water to the dough, a tablespoon at a time, until a test piece does not crack.
Divide the dough into 24 golf ball size pieces for tacos and 12 large balls for quesadillas. Place on a platter and cover with a damp towel. Line a tortilla press with 2 sheets of plastic cut from a plastic freezer bag or other heavy duty plastic bag.
Heat a dry cast iron skillet, or non-stick pan until moderately hot. Flatten each ball of dough in the tortilla press, then remove the plastic from the top and, holding the tortilla with your fingertips, peel off the bottom sheet. Lay the tortillas one by one on the skillet and cook about 30 to 45 seconds per side, pressing the top of each tortilla with your fingertips to make it puff. Place the hot tortillas on a towel.
When they are still warm but not hot, stack and wrap in a towel. Serve immediately or let cool, wrap well in plastic or a plastic bag and store in the refrigerator up to a week.
c.1997, M.S. Milliken & S. Feniger, all rights reserved