Remove the stems and seeds from the guajillo, ancho, and arbol chilies. Rinse them under cool water, then place them in a saucepan. Add enough water to cover and bring to a simmer over medium heat for about 15 minutes until softened.

Preheat your broiler to high and place the tomatoes, onion, and unpeeled garlic on a baking sheet. Broil for 4-6 minutes, turning occasionally until lightly charred. Let them cool slightly.

In a blender, combine the softened chilies (and simmering water), charred tomatoes, onion, garlic, beef broth, and spices. Blend on high until smooth.

In the slow cooker, place your beef chunks. Pour the blended sauce over the beef, ensuring it’s fully coated. Toss in bay leaves, cover, and cook on low for 8-9 hours or high for 4-5 hours.

Once done, remove bay leaves. Shred the beef inside the slow cooker with two forks, mixing it back into the sauce.

Serve your birria stew in bowls with broth or use as a filling for tacos. Garnish with toppings like diced onions, fresh cilantro, and lime juice.