Making Birria Quesadillas involves a few key steps. Follow these instructions to create this amazing dish:

1. Prepare the Chilies: Remove the stems and seeds from the guajillo and ancho chilies. Soak them in hot water for about 15 minutes until soft.
2. Blend the Sauce: In a blender, combine soaked chilies, onion, garlic, beef broth, apple cider vinegar, cumin, oregano, cinnamon, and a pinch of salt. Blend until smooth.
3. Cook the Meat: In a large pot or Dutch oven, add the beef and pour the blended sauce over it. Bring to a boil, then reduce the heat to low, cover, and simmer for about 1.5 hours or until the meat is tender.
4. Shred the Meat: Once cooked, remove the beef from the pot and shred it using two forks. Return the shredded meat to the pot to soak up the sauce.
5. Assemble the Quesadillas: Heat a skillet over medium heat. Place a tortilla in the skillet, add a layer of cheese, then a generous portion of shredded birria, and more cheese on top. Top with another tortilla.
6. Cook the Quesadilla: Cook for 2-3 minutes on each side, or until the tortillas are golden brown and the cheese has melted. Remove from heat and repeat with the remaining tortillas and filling.
7. Garnish: Cut the quesadillas into wedges and sprinkle with chopped cilantro.