Sauce:
3 Tablespoons butter
2 large cloves garlic, minced
1 teaspoon ground cumin
1 teaspoon fresh chili powder
3 Tablespoons all-purpose flour
¾ cup chicken stock or broth
¾ cup buttermilk
salt and freshly ground black pepper to taste
Filling:
2 Tablespoons olive oil
1 medium onion, chopped
1 large green bell pepper, chopped
1 medium poblano pepper, chopped
2 plum tomatoes, peeled, seeded and chopped (or ½ cup canned tomatoes, drained)
¼ cup diced green chiles
3 to 4 cups cooked, coarsely shredded chicken (white and dark meat)
⅓ cup green onions, including tops, chopped
canola oil for softening tortillas
8 corn tortillas
2 cup grated Longhorn or Monterey Jack cheese