Chicken Birria Tacos for the slow cooker is chicken cooked in a smoky sauce, even straight from frozen, until it shreds for an easy, dump-and-go dinner.
Put the dried chile negro, chipotle, and New Mexico chiles in a bowl. Cover completely with hot water and let them soak until fully softened.
Transfer the softened chiles to a blender with 2 cups of the soaking liquid.
Add the diced tomato, onion, garlic, chicken base, cumin, and oregano. Blend until smooth.
Pour the sauce into a saucepan, add the bay leaf, and simmer, stirring occasionally, for about 20 minutes, until it reduces and thickens.
Place the chicken breasts in the slow cooker. Pour the sauce over the chicken so the pieces are well covered.
Cover and cook on low for about 5 hours, plus roughly 30 extra minutes if the chicken starts frozen.
Once the chicken shreds easily, remove it and shred it. A stand mixer with the paddle attachment on low speed shreds a full batch in under a minute.
Warm the corn tortillas; microwave for soft, or fry and dip ahead of time if you prefer them crisp.
Set out the chicken and sauce along with tortillas, cheese, cabbage, salsa, and guacamole, so everyone can build their own taco and dip the tortilla in the sauce at the table.
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