Makes 16 meatballs; serves 4 to 6
2 tablespoons white rice
5 eggs
1½ pounds ground beef
1/2 of a small white onion, finely chopped (about ½ cup)
2 cloves garlic, minced
3 tablespoons finely chopped cilantro
1 tablespoon olive oil
2 teaspoons kosher salt
2 cups tomato sauce
1 cup chicken stock
1 tablespoon minced chipotle chiles in adobo sauce plus 2 teaspoons adobo sauce
2 cinnamon sticks
1 bunch spinach, stemmed and washed (about 4 cups)
Put the rice in a small bowl and add cold water to cover. Let soak 20 minutes, then drain. Put 4 of the eggs in a medium saucepan (reserve the fifth egg) and add cold water to cover. Bring to a boil over high heat, boil for 1 minute, then remove from the heat and cover. Let stand 9 minutes, then transfer the eggs to an ice-water bath. When cool, peel the eggs and quarter them. Set aside.
In a large bowl, add the rice, beef, white onion, garlic, cilantro, olive oil, salt and the remaining (raw) egg and mix well to combine. Take a small amount of the meat mixture and use your hands to form into a thin patty. Place one quarter of hardboiled egg in the center of the patty, then form the meat mixture around the egg, enclosing it completely, and shape into a sphere. Repeat with the remaining meat and eggs until you’ve formed all 16 meatballs.
Pour the tomato sauce and chicken stock into a large high-sided saucepan or pot. Add the minced chipotles, adobo sauce and cinnamon sticks and stir to combine. Put the meatballs in the pot, arranging them snugly in a single layer (the meatballs will be poking out of the sauce). Bring the sauce to a boil over medium-high heat, then reduce the heat so the sauce is simmering gently. Cover and cook for 15 minutes.
Use a slotted spoon to transfer the meatballs to a rimmed dish. Remove the cinnamon sticks from the sauce and discard, then increase the heat so the sauce is simmering vigorously. Stir in the spinach and cook until the spinach is wilted, about 5 minutes. Return the meatballs to the sauce until rewarmed, about 5 minutes. Serve hot, accompanied by white rice.