Rehydrate the chilies, cover chilies with hot water and soak for 20 minutes.
Heat olive oil in cast iron pan or dutch oven over medium-high heat.
Add half of the tomatoes, onion, and garlic, the chilies (remove from soaking liquid) and saute until they begin to soften. Add a splash of the chili water and let cook down for about 5 minutes.
Remove from the pan and put in a food processor or blender.
Give the beef cubes a bit of a dusting with the all purpose rub.
Add a splash of oil to the pan and put the beef cubes in to sear, stirring occasionally, for 5-6 minutes, until all sides are browned.
Stir in the other (uncooked) half of the onions, tomatoes and garlic. Give a light dash of salt and pepper.
Continue cooking for 4-5 minutes, stirring occasionally.
Give the ingredients in the food processor or blender a whiz until a smooth paste forms. Add a few tablespoons of the reserved soaking liquid if too thick.
Stir in the remaining reserved soaking liquid, potatoes, oregano, and 3 cups of stock and water and bring to a simmer. Salt and pepper again, lightly.
Transfer the chili mixture to the simmering chili and mix well.
Continue simmering chili for 1 hour, stirring every 20 minutes, until potatoes and meat are tender.
Season with salt and pepper at the 40 minute mark, if needed.