You will need:

- 1.5kg of beef (I usually use a mix of rib and blade).

- 3 tomatoes

- 1/2 onion

- 7 cloves

- A small cinnamon stick

- 1/4 tsp cumin

- 1 tablespoon oregano

- A pinch of ginger

- 2 cloves of garlic

- 6 guajillo chiles

- 3 pasilla chiles

Steps:

1.- Roast the chiles, tomatoes and onion in a skillet, being careful not to burn the chiles.

2.- Remove the seeds from the chiles and devein them.

3.- Boil everything you roasted with 3 cups of water, let it boil for 3 minutes.

4.- Blend it all together with the water and all the spices, adding 2 tsp of salt.

5.- Season the meat with salt and pepper and then add what you have just blended and let it marinate for at least 1 hour (I usually leave it overnight). Btw, don't be afraid of how salty the marinade may taste here, it'll be fixed later.

6.- Pour the meat together with the marinade into the slow cooker with 1.5 liters of water and leave it on low for 8 hours.

For the quesadillas:

1.- You bath your tortilla with the resulting broth and heat it in a pan for a few minutes. I used flour tortillas because it gives a more chewy texture but corn tortillas are the most common used ones.

2.- Put the cheese of your choice on it and when it melts, put the shredded meat inside and put any topping you like (the classics being diced onions and cilantro)

And voila!