Tender pieces of flank steak are simmered in their own juices creating a rich and super flavorful broth for the Carne en su Jugo (a.k.a. Meat in its Juices) that we’ve all grown to love.
Combine the tomatillos, serrano peppers, garlic, and water in a small saucepan over medium-high heat; bring to a boil, cover, and simmer for 10 minutes. Remove the pan from the heat and allow to cool. Transfer the contents to a blender and blend until smooth. Set aside.
Cook the bacon in a large pot or dutch oven over medium-high heat until crispy, about 10 minutes. Drain on a paper towel-lined plate. Crumble the bacon and set aside.
Drain the bacon grease, leaving a tablespoon or so in the pot. Add the flank steak to the hot pot and cook until completely browned. Pour the tomatillo mixture over the beef and bring to a boil.
Stir the chicken bouillon into the mixture, and reduce heat to medium. Cover the pot and simmer until tender, at least 30 minutes and up to 1 hour.
Stir the pinto beans into the flank steak mixture and simmer a few minutes until warm; divide the mixture between 6 bowls. Garnish each with bacon, onion, cilantro, black pepper, and a lime wedge.