Cut chile tops off and remove the seeds with a knife or spoon.

In a food processor, combine chiles, garlic cloves, white onion, roma tomatoes, cinnamon stick, peppercorns, chili powder, cumin, and paprika. Blend or pulse until ingredients are nearly smooth and well blended.

Place beef chuck roast in the crock pot. Pour in the birria sauce mixture.

Add 1 cup water to the top, along with 2 bay leaves and 3 tablespoons vegetable oil.

Slow cook on low for 10 hours or until fork tender.

Shred meat in a bowl using two forks and add 1 cup birria sauce from the slow cooker to the bowl. Save the remaining sauce for later.

To prepare the tacos, add a corn tortilla to a medium hot skillet. Oil the pan, lay down the tortilla, top it with shredded cheese, flip it, and let it get nice and golden brown and crunchy.

Top the upward facing side with shredded beef, cilantro, onion, and lime juice, then fold it in half.

Pour slow cooker sauce into a bowl and serve tacos with sauce to dip into.