Prepare tomatoes: Roast the tomatoes lightly until cooked but not overly charred.
Prepare onion and garlic: Chop half an onion and 4 garlic cloves into small pieces for grinding.
Grind onion, garlic, and pepper: In a mortar, grind the chopped onion, garlic, black pepper, and a little salt until well combined.
Season chicken: Spread the ground onion, garlic, pepper, and salt mixture evenly over the 2 kg of washed chicken using your hands.
Brown chicken: Heat a pot and brown the seasoned chicken pieces evenly on all sides.
Prepare chipotle tomato sauce: Chop the roasted tomatoes and chipotle chili in adobo into smaller pieces. Grind them together with a little water, salt, and pasote sprigs until smooth.
Cook chicken in sauce: Add the chipotle tomato sauce to the browned chicken in the pot. Cook until the chicken is fully cooked and tender.
Serve: Serve the chipotle chicken hot, ideally with white rice or beans.