Step 1: Boil the tomatoes to soften skin. Peel them and place into a blender with garlic, cumin, pepper and cup of water. Blend until you get a light sauce.
Step 2: In a sauté pan heat the oil over medium heat. Add onions and chilies
Step 3: Add the ground meat and break it with the back of a spoon cooking for 5 minutes or until changes its color.
Step 4: Pour in the tomato sauce and mix. Add water or beef stock enough to slightly cover the meat. Season with salt.
Step 5: Add potatoes to the pan, mix, and cover again. Cook until tender