Begin by prepping the chilies. Slice off the stems and remove the seeds. Place in a pot with water, bring to a simmer for 15 minutes, then set aside.

Preheat the broiler. Arrange tomatoes, onion, and garlic on a baking sheet. Broil for 4-6 minutes until charred.

In a blender, combine softened chilies, roasted vegetables, broth, vinegar, and spices. Blend until smooth.

Place beef in a slow cooker, pour the sauce over, and cook on low for 8-9 hours or high for 4-5 hours.

Shred the beef in the slow cooker, mixing it back into the sauce.

Serve birria in bowls or tacos, garnished with onion, cilantro, and lime.