Add peppers and 2 cups of water to saucepan and bring to boil.
On medium heat place a medium skillet with olive oil and add onion, tomatoes, and garlic cloves. Cook until tomatoes and onion are soft, about 10 minutes. Set aside.
Use a new skillet and place over medium heat. Add cumin seeds, whole cloves, peppercorns, and cinnamon stick. Toast until aromatic, about 5-7 minutes.
Using small blender, grind toasted spices except cinnamon.
Add chiles, tomato mixture, ground spices, cinnamon, oregano, marjoram, water, and salt to a blender. Blend until smooth (about 5 minutes).
Strain sauce with fine strainer.
Birria (Slow Cooker)
In a large dutch oven or skillet over medium heat add olive oil
Once oil is hot, add beef and sear each side until just browned.
Add beef, sauce, water, vinegar, and bay leaves to slow cooker. Cover and cook on high for 4-5 hours, or low 8-10 hours. The meat becomes more tender the longer you leave in the crockpot but will be thoroughly cooked and tender at the lesser times.