Warm the pan: Heat a large skillet over medium-high. Add oil if using lean beef.
Brown the beef: Add ground beef and break it up with a spatula.
Cook until no pink remains and edges get slightly crisp, about 6–8 minutes. Season lightly with salt and pepper.
Sauté aromatics: Push beef to one side. Add onion and bell pepper to the empty space.
Cook 3–4 minutes until softened. Stir in garlic and cook 30 seconds until fragrant.
Add spices: Sprinkle in smoked paprika, cumin, oregano, and red pepper flakes. Stir to coat the beef and veggies so the spices bloom in the fat.
Build the sauce: Stir in tomato paste, then add diced tomatoes and beef broth.
Scrape up any browned bits from the bottom of the pan.
Simmer: Reduce heat to medium-low. Let it bubble gently for 8–10 minutes, stirring occasionally, until slightly thickened.
Finish: Stir in butter for a glossy finish. Taste and adjust salt and pepper.
Serve: Spoon over cauliflower rice, toss with zucchini noodles, or plate with a side of greens.
Top with shredded cheese and fresh herbs if you’d like.