For the Brisket:
Preheat the oven to 350 degrees F.
In a small bowl combine chili powder, salt, garlic and onion powders, black pepper, brown sugar, dry mustard, paprika, cumin, and bay leaf. Season the raw brisket on both sides with the spice rub, concentrating on the meat side. Place in a roasting pan, fat side up, and roast, uncovered, for 1 hour.
Add beef stock and enough water to yield about 1/2 inch of liquid in the roasting pan. Lower oven to 300 degrees F, cover pan tightly with lid or aluminum foil and continue cooking for 3 additional hours, or until fork-tender.
Let brisket set until cook enough to handle. Using forks or fingers, bull brisket apart.
For Salsa Verde:
In a medium saucepan combine tomatillos, onion, jalapeno, garlic, water, oregano, cumin, coriander, salt and pepper. Bring to a boil. Reduce heat to simmer, cover and cook 25 to 30 minutes, until tomatillos break down. Using and immersion blender, puree the sauce in the pot.
To Assemble Enchiladas:
Preheat oven to 350 F. Spread 1/2 cup salsa verde into bottom of 4 quart baking dish.
Heat tortillas until pliable. Spread a tablespoon on one side of the tortilla. Top with some brisket and crumbled queso fresco. Roll tortilla around brisket and cheese and place seam side down in prepared baking dish. Continue with remaining tortillas until baking dish is full. Top rolled enchiladas with more of the salsa verde and sprinkle with cheese. Cover baking dish with cover or aluminum foil. Bakein preheated oven 30 to 35 minutes until cheese is melted and enchiladas are heated through. Makes 12 enchiladas.