1 1/2 canned chipotle chiles in adobo sauce, stemmed
3/4 teaspoon whole-grain mustard
3/4 teaspoon ancho chile powder
1/2 bay leaf
Pinch of ground allspice
1 cup chicken stock or canned low-sodium broth
3/4 cup chili sauce
1/2 cup canned plum tomatoes
Salt and freshly ground pepper
Heat the oil in a medium saucepan. Add the onion and cook over moderate heat, stirring, until browned, about 10 minutes. Add the garlic and cook for 2 minutes, then add the bourbon and simmer for 2 minutes longer. Stir in the vinegar, sugar, chipotle chiles, mustard, ancho chile powder, bay leaf and allspice and bring to a boil. Cover and cook over low heat for 30 minutes.
Add the chicken stock, chili sauce and tomatoes, cover partially and cook over low heat until reduced by half, about 1 hour. Remove from the heat and let cool. Discard the bay leaf. Transfer the sauce to a blender and puree until smooth. Season with salt and pepper.