Heat the oil in a medium to large pot, add the diced red onion, crushed garlic, achiote powder, ground cumin, dry oregano and salt. Cook for 3-5 minutes over medium heat or until the onions are soft and translucent.
Add the pieces of pork and potatoes, stir and mix until well coated with the onion refrito mix. Cook for about 5 minutes.
Add the water or broth and bring to a boil.
Cook for 35-40 minutes or until the meat and potatoes are tender.
Add the oats and carrots, cook for another 15-20 minutes. Taste and add salt/pepper to taste.
Mix in the chopped cilantro and green onions.
Serve with avocado and your favorite aji style hot sauce.