150 gr (5,3 oz) pork cracklings
680 gr (1.5 lb) tomatoes
2 pasilla chillies
chile de árbol chillies (read notes)
75 gr (2/3 cup) onion
1 garlic clove
1 tbsp pork lard
Place the tomatoes and chillies in a pot. Cover with water and boil until the chillies are soft and the tomatoes begin to peel (about 10 minutes).
Let tomatoes and chillies to cool for 5 minutes and then transfer to a blender. Add two or three cups of the cooking water, the onion and the garlic. Blend for 10 seconds or more (SEE NOTES).
In a saucepan, heat the pork lard over medium heat. Add the sauce that you just prepared and a pinch of salt. Mix and cook for 5 minutes.
When the sauce starts to simmer, add the pork cracklings then with a spoon push them down so that they begin to soak up the sauce.
Simmer for 15-20 minutes with the pan covered, always checking that there is a little sauce and the cracklings do not dry out (see video).
When the sauce has thickened and chicharrones are soft, adjust salt to taste, turn off the heat and let chicharrones en salsa roja sit for 10 minutes before serving.