Put all the ingredients for the sauce in a blender and blend until smooth. Set aside.
Season chicken with salt and pepper, skin side first.
Heat the oil in a large pot or Dutch oven over medium-high heat. Add the chicken skin side down and season again on the opposite side. Brown for about 4-5 minutes on each side.
Add the potatoes, cassava, tomato sauce, water, aliños and stir well. Bring to a boil, cover, lower heat to medium-low, and cook for 30-35 minutes or until the chicken is fully cooked and the potatoes and cassava are fork tender.
Once cooked, taste for seasoning and add more salt if needed. Garnish with chopped cilantro and serve with white rice and avocado.
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Notes
You can use your favorite type of potatoes. Red potatoes tend to be more firm. Russet and yellow potatoes tend to dissolve faster than red potatoes but this will add a delicious thickness to the sauce.
Add as much or as little water as you want depending on how thick or thin you want the sauce.