Prep the aromatics: Chop the onion and bell pepper.
Mince the garlic. Open the tomatoes and measure spices so everything’s ready.
Brown the beef: Heat a large skillet over medium-high. Add olive oil if using lean beef.
Crumble in the ground beef and cook, stirring, until mostly browned, about 5–7 minutes. Drain excess fat if there’s a lot.
Add vegetables: Stir in onion and bell pepper. Cook until softened and lightly golden, about 4–5 minutes. Add the garlic and cook 30 seconds, just until fragrant.
Season it right: Sprinkle in cumin, smoked paprika, oregano, red pepper flakes, 1 teaspoon salt, and 1/2 teaspoon black pepper.
Toast the spices for 30–60 seconds to wake up their flavor.
Build the sauce: Stir in tomato paste and cook 1 minute. Add diced tomatoes and beef broth. Scrape up any browned bits from the pan for extra flavor.
Simmer and thicken: Reduce heat to medium-low and simmer 8–10 minutes, stirring occasionally, until the mixture thickens and the flavors meld.
Taste and adjust salt and pepper.
Finish and serve: Remove from heat. Stir in chopped cilantro or parsley if you like. Spoon over rice or pasta, tuck into tortillas, pile onto buns for sloppy joes, or use as a hearty filling for stuffed peppers.