Mix the seasoning in a small bowl. Toss the beef with it until coated, and let it sit 10 minutes.
1 tablespoon chili powder, 2 teaspoons ground cumin, 1 teaspoon Mexican oregano, 1 teaspoon garlic powder, 1 1/2 teaspoons salt, 1/2 teaspoon black pepper, 1 tablespoon cornstarch, 2.5-3 pounds beef chuck roast
Heat the oil in a Dutch oven or large deep skillet over medium-high heat. Sear the beef in batches until browned on all sides, 4 to 5 minutes per batch. Set aside.
2 tablespoons oil
Lower the heat to medium. Add the onion, bell pepper, poblano, and jalapeños. Cook 5 minutes until softened, then add the garlic and cook 1 minute.
1 medium white onion, 1 green bell pepper, 1 poblano pepper, 2 jalapeños, 4 garlic cloves
Add the fire-roasted tomatoes and broth, scraping up the browned bits. Return the beef and any juices.
1 can fire-roasted diced tomatoes, 1 cup beef broth
Bring to a simmer, cover, and cook on low 45 minutes.
Uncover, stir in the Roma tomatoes, and simmer 30-45 minutes, until the sauce thickens and the meat turns fork-tender.
2 Roma tomatoes
Finish with lime juice and cilantro. Taste for salt. Serve in tortillas, over rice, or in bowls.
1/2 lime, Fresh cilantro