6 ancho chiles
10 pasilla chiles
2 cups hot water
1 1-inch cinnamon stick
5 whole cloves
6 black peppercorns
1/4 teaspoon thyme
1/4 teaspoon marjoram
1/4 teaspoon cumin
6 cloves garlic, peeled
2 tablespoons mild white vinegar
2 bay leaves
2 tablespoons sugar
3 cups chicken stock

Toast chiles in shallow pan in a 300-degree oven until slightly charred, 4 to 5 minutes, watching carefully and turning occasionally. When cool enough to handle (wear latex gloves if skin is sensitive), slit and remove seeds. Soak in hot water 20 minutes. Transfer chiles and 1 cup of the water to blender. Add all ingredients except vinegar, bay leaves, sugar, and stock. Blend well. Combine with remaining ingredients in saucepan. Simmer for 15 minutes, until sauce thickens.