As far as recipes go, it doesn't get easier than this. I was once told that this dish is Mexican in origin, but to me it represents the fusion of cultures that comes of the Romance Languages Department that I've called home for the past 6 years.
8 chicken thighs (it's perfectly OK to leave the bones in and the skin on)
1/2 cup + 2 Tbsp olive oil
Salt and Pepper
1/2 cup balsamic vinegar
1/2 large sweet onion, sliced
3 dried ancho chiles, rehydrated and some of the seeds removed
1. In a dutch oven or large wide bottomed pot, heat 2 Tbsp of olive oil
2. Season the chicken liberally with salt and pepper.
3. Being sure not to crowd the pot, brown the chicken on both sides. (You may need to do this in batches.)
4. Add the remaining ingredients and allow to stew, covered, over medium heat for 30 minutes.
Serve over rice.