Heat olive oil in a small skillet over medium-high heat, add the sliced onions and sauté until translucent, about 5 minutes.
1 tablespoon olive oil, 1 medium onion
Transfer onions to the slow cooker. To a blender, add tomatoes, garlic, cumin, oregano, and chilis in adobo sauce. Pureé until blended into a sauce.
3 cloves garlic, 1 teaspoon cumin, 1 teaspoon oregano, 15 ounce can tomato puree, 2 chilis in adobo sauce + 1 tablespoon of the adobo sauce the chili’s are in
Pour the sauce over the chicken and onions. Cook on high for 2-3 hours or low for 4-6 hours.
Once the chicken is cooked through, remove the thighs to a cutting board and shred with two forks.
Return the meat back to the sauce. Let it simmer for 20-30 minutes on low or warm setting.
Serve over tortillas with red onion, cilantro and cheese.
Notes
The heat in this recipe is medium.For mild, use 1 chili and 1 teaspoon of adobo sauce; for hot, use 3 chilis and 2 tablespoons of the adobo sauce.This can also be made with boneless skinless chicken breasts.Shredding chicken hack: If you have a stand mixer, place the thighs in the bowl of the stand mixer, use the paddle attachment, and turn the mixer to ‘stir’ or a low setting, run until chicken is shredded.Your favorite cheese can be substituted for the Cotija cheese.