Oaxacan Moles are the best known.

.25 lbs chiles mulato (chilhuacle) washed, seeded and deveined
.25 lbs chiles pasilla (guajillo) washed, seeded, and deviened
2 C lard (vegetable oil)
8-9.5 C chicken broth
4.5 medium white onions
3.5 heads garlic
.5 whole nutmeg
2 oz ginger root
6 marjoram sprigs
1.5 tsp whole cloves
10 whole allspice
1 C sesame seed
.75 C prunes, pitted
1 tortilla
5 tomatillos, husked
5 lg tomatoes
2-3 avocado leaves
2 bay leaves
12 oz mexican chocolate (semi-sweet baking chocolate)
1 C bread crumbs

On the comal (or heavy skillet over direct heat):

Roast the chiles (being careful not to char) and puree with 3 C chicken broth in a blender (food processor) and reserve.

Roast the onions, garlic heads , remove
Brown the nutmeg, ginger, marjoram (lightly), cloves and allspice, remove
Brown the sesame seeds until very dark, remove
Lightly brown the prunes, remove
Toast the tortilla until charred, remove
Roast the tomatillos, tomatoes and avocado leaves, remove
Heat 2 T lard ( vegetable oil) and fry bay leaves.

Puree all ingredients in a blender (food processor) add chicken broth if necessary to thin.

Heat lard (vegetable oil) in stockpot
Brown onion until a dark rich color, remove and discard.
Add pureed fruit and spice mixture to lard and cook on low till it renders the fat ( 45 min)
Stir in the pureed chiles and cook slowly or 1.5 hrs.
salt to taste
Add chocolate and sugar to taste
Add bread crumbs and continue cooking till fat is rendered.

Add chicken broth until mole is semi-thick in consistency, Mole should be thicker than most
Strain to make a very smooth sauce.