Squeeze the lemon juice into a blender and add the water and the chicken stock.
Remove the seeds and the stems of the arbol peppers and add the arbol peppers to the blender. To add additional heat to the potatoes some or all of the seeds can be added to the blender. Blend at high speed until smooth sauce.
Heat up a deep pot, add the potatoes and the sauce. Cook the potatoes between 40min and 1h at low to medium heat in the covered pot.
Once the potaotes feel soft when you poke them with a steak knive they are ready to serve.
Once the potatoes are done cooking and still have alot of sauce you can uncover the pot and continue cooking until most of the liquid has evaporated.