1.Season beef with salt and pepper. In a large skillet, heat 2 teaspoons oil over high. In two batches, cook beef until browned on all sides, 5 minutes per batch (add 2 teaspoons more oil for second batch). Transfer to a 5- to 6-quart slow cooker.

2.In same skillet, cook 2 teaspoons oil, onion, bell pepper, jalapeno, and garlic over medium, stirring and scraping up browned bits with a wooden spoon, until vegetables are tender, 5 minutes. Add cumin, chili powder, oregano, and flour and cook 1 minute. Slowly pour broth into skillet, stirring until liquid is smooth. Simmer 2 minutes, then transfer mixture to slow cooker, along with tomatoes and bay leaves. Season to taste with salt and pepper and stir to combine. Cover and cook on high 6 hours. Serve in tortillas with cheese and cilantro. (Refrigerate cooled mixture in an airtight container, up to 3 days, or freeze, up to 2 months.)