1For the broth:
On medium heat, in a pot, saute the onion, garlic and cumin seeds in the olive oil until the onions are translucent. Add tomatoes and continue to simmer slow and low. It's ready when the tomatoes are cooked down and it looks saucy. You may need to add a little broth. At this point, either transfer tomato sauce to a blender jar with the chipotles, or if you have a hand-held blender, throw the chipotles in the pot and blend there with a little broth. When your tomato sauce is smooth, transfer back to the pot, add all of the broth, carrots, potatoes and fresh herbs, S&P, cover, and bring to a steady simmer for about 20 minutes or so. (I like to add zucchini, and kale if I have it. Add it a little later though.)
In a large bowl, combine ground beef and pork, rice, oregano, egg, S&P with your hands. It's fun. Form into balls, size is up to you. I wouldn't recommend larger than baseball sized or they might fall apart. Gently add the meatballs to the soup one at a time. When they are good and buoyant and firm, they're done. Serve in deep bowls. Have fresh, chopped white onion, cilantro, lime wedges and chopped avocado for a garnish, and of course, plenty of warm corn tortillas! ¡Buen provecho!