Put the tomatillos and the peppers in a Dutch oven, or a large pot. Cover the vegetables with cold water. Add 2 of the eggs.
Bring to a boil over medium heat, then decrease the heat to a simmer.
After about 6 minutes, remove the eggs with a slotted spoon to a bowl of cold water.
Continue cooking the tomatillos and peppers for another 15 minutes.
Let the vegetables cool somewhat. Place the peppers on a cutting board and use a knife to remove the stems. Cut the peppers open and scrape out the seeds. For an extra spicy sauce, leave some (or all) of the seeds in the pepper.
Use a slotted spoon to transfer the vegetables to a blender. Add the garlic, cumin, cilantro, and stock and pulse until slightly puréed.
In the same pot that you boiled the veggies in, or in a new large skillet, add the oil over medium-high heat. Add the sauce and cook, stirring often, until slightly thickened, about 10 minutes.
Prepare the Meatballs
Peel the eggs and chop them into small to medium-sized dice.
Pour the milk over the breadcrumbs in a mixing bowl and let stand for 5 minutes, without stirring.
Add the ground beef, pork, chopped hard-boiled eggs, chipotle, adobo sauce, parsley, raw egg, salt (1 tsp), and pepper (½ tsp). Use your hands, or a spatula, to mix the ingredients all together.
Dived the meat into 12 equal parts and roll them into balls. Each ball should weigh about 2.2 ounces.
Reheat the salsa sauce to a simmer. Gently place the meatballs into the sauce.
Simmer for 40 minutes, turning the meatballs over after 20 minutes.
Serve in bowls garnished with cilantro and crumbled Mexican cheese (Cotija). Drizzle some of the salsa over the meatballs and pass the rest at the table.
See the video near the top of the blog post for visual guidance. If you liked the video, please subscribe to our YouTube channel. If you can't find tomatillos, you can go with green tomatoes and add about 1 tsp of fresh lime juice to the blender. Sometimes you can find canned tomatillos in the Hispanic section of your grocery store. Bottle green sauce (verde) is just fine. Skip making the sauce and simmer in two cans or bottles of store-bought sauce. The salsa can be made up to 3 days in advance. The sauce can be frozen for up to 2 months. The meatballs (with sauce) will keep covered in the fridge for up to 5 days. They can be frozen for up to 1 to 2 months.