Add onions and bell peppers. Cook until onions are translucent and soft.
Add garlic, cayenne pepper, cumin, paprika, and oregano. Stir until fragrant (about 1 minute).
Add meat back to pan with salt, pepper, diced tomatoes, chicken broth, and bay leaves.
Bring contents of the pan to an aggressive simmer, and simmer uncovered for 1 hour, 45 minutes to 2 hours — or until the sauce is thick (see note below).