Chop your roast into small chunks 4 inches or so, all the same thickness.
Fill a large pot with beef shanks, and cut up pieces of chuck roast and fill with water. I quickly realized I needed to change pots, mine wasn't large enough initially. Make sure your pot is big enough to hold the meat. Then add in 1 onion, cut in half, 8 garlic cloves, 4 bay leaves, and 1 T salt . Place over a medium heat. As the meat starts to boil, make sure to skim all the impurities off the top to create a clean broth.
While the meat cooks, prepare the sauce. Start by removing the stems and all seeds from the dried chilies and placing them in a pot covered with water and bring to a boil. Once they come to a boil, simmer for 15 minutes, and set aside.
In a separate pot, add the tomatoes and bring to a boil until they are softened. Set aside.
Transfer the chilies to a blender or food processor (reserving all the liquid). To the blender or food processor, add black pepper, cumin, marjoram thyme, oregano, ginger, cinnamon, apple cider vinegar, cloves, 1/2 onion, chipotle pepper, 8 garlic cloves, softened tomatoes, and 1 cup of the cooking liquid.
Blend until smooth. If consistency is too thick, add a little more of the cooking liquid.
At this point, you want to get a strainer and place it over your meat that is cooking over the stove top. Slowly start adding your blended chilies into the strainer, making sure all the sauce is draining into your meat. Make sure to press as much of the liquid out of the ground chilies. If needed, add a little more cooking liquid (but not too much). I did this before, and added too much of the cooking liquid and my sauce wasn't as flavorful. So just add enough to get as much of the yummy blended chile flavor out as you need to. Then mix all the sauce in to your pot of meat. Let simmer for 3 hours. Until the meat is soft enough to pull apart easily.
Add all your meat to a large bowl, and shred all chunks. This is your yummy taco meat. Save your pot with all the sauce to fill individual bowls for dipping tacos into. At this point, you can choose to use your favorite tortilla. I used a low carb tortilla from Mr. Tortilla link above only 1g net carbs per tortilla.
For a traditional Birria taco, you usually fill the taco shell with meat and cheese and fry in a frying pan with a little sauce, creating what is similar to a quesadilla. I chose to eat mine like a traditional taco, and stuffed it with meat, and cheese, onions and cilantro. Dipping in the sauce before every bite. This was a yummy yummy dinner the whole family enjoyed!