Begin by combining 10 Guajillo Chiles, a whole head of garlic, 3/4 cup of apple cider vinegar, 2 teaspoons of oregano, 1 teaspoon of cumin, salt, and pepper in a bowl to create a marinade.
Using kitchen shears, carefully cut along the breast bone of the chicken to prepare it for seasoning.
To season the chicken, sprinkle salt, pepper, and garlic over the top.
Reserve 1 cup of the marinade for basting later.
Once that is done, add the rest of the marinade to the chicken and place it on a preheated grill at 300 degrees.
When the internal temperature of the chicken reaches 155 degrees, baste it with the reserved marinade.
When the chicken has reached an internal temperature of 165 degrees, it is ready to be removed from the grill.
Allow the chicken to rest for 10 minutes before serving it.
Finally, enjoy your delicious chicken!