Remove the stems and seeds from the geen chiles. Lightly brush them with oil. Roast in preheated air fryer at 400 degrees for 10 minutes, turning as needed. Place in plastic bag or covered storage container. set aside.
In a large cazuela or pot, preheat 3 tablespoons of avocado oil for 4 minutes at medium heat. When ready add the beef. Season, to taste, with salt and pepper. Stir the beef as needed until browned all around and most of liquid has evaporated.
Add the onions. Stir well to combine and sauté for 5 minutes.
In the blender, combine the tomatoes, garlic, 1 3/4 cups of water or broth. Blend on high until mostly smooth. Pour into cazuela with beef. Stir well to combine. Cook at a light simmer while you fry the potatoes.
Preheat 3 tablespoons of avocado oil in a large skillet. When ready add potatoes. Fry the potatoes for 8-9 minutes, turning as needed. Add the serrano peppers and continue cooking for another 3 minutes. When ready, drain any excess oil, then add potatoes to the beef. Stir well to combine. Cover 3/4 of the way.
While beef is simmering, peel the blistered skins from the green chiles. Dice or sliced to desired size. Add green chiles to the beef. Stir well to combine and continue simmering for another 5 minutes. If using ground spices, add them at this time. Stir well. If using whole spices, you can grind them in the molcajete or mortar and pestle. Add a splash of water to the molcajete, then pour into beef. Simmer for 5 more minutes. Taste for salt.
Serve with your favorite rice and beans on the side. Don't forget the warm tortillas!