Begin by prepping the ingredients. First prepare the taco topping of the 1/2 white diced onion and cilantro. Place in a container and set aside. Set aside the other half of the diced onion for the birria. Also smash the garlic. Then deseed the chiles. Lastly, Place meat in a bowl with water and vinegar. Let soak for a few minutes then rinse and pat very dry. Season with salt and pepper. In a large stock pot, add a bit of oil and let it heat up. Add meat in batches and brown on all sides.
While browning, in a separate pan add deseeded chiles, coriander, black peppercorn, and cloves and toast until fragrant.
Separate the chiles from the spices. Add the spices to a cheesecloth along with the bay leaves and cinnamon sticks. Tie and set aside.
All meat should be browned by this point and be removed from pan. Add a little fresh oil to the bits of the pan and add the remaining diced onion and smashed garlic.
Once onions are translucent add tomato paste and mix till melded together. Then add in the beef stock.
Return beef, chiles, and spice bag to pot. Bring to a simmer and cover and cook for about 1 hour.
After an hour remove the chiles and onions and add to a blender with a little bit of chipotle peppers in adobo sauce (optional for more spice).
Pour blended mixture back into meat and cover and cook for 1-2 hours or until meat is tender enough to shred with a fork.
Shred your cheese if needed at this point to prepare for the assembly