Brown the beef: Heat a large skillet over medium-high. Add the ground beef and break it up.
Cook until browned and no longer pink, about 5–7 minutes. Drain excess fat if needed, leaving about a tablespoon for flavor.
Add aromatics: Stir in the diced onion and cook 2–3 minutes until softened. Add the garlic and cook 30 seconds, just until fragrant.
Season: Sprinkle in chili powder, paprika, oregano, salt, and pepper.
Stir to coat the beef and onions, letting the spices bloom for 30 seconds.
Stir in tomato base: Mix in tomato paste and diced tomatoes with their juices. Let it bubble for a minute to marry the flavors.
Add rice and liquid: Pour in the rice and beef broth. Stir well, scraping any browned bits from the pan.
Bring to a gentle boil.
Simmer: Reduce heat to low, cover, and cook 15–18 minutes, until the rice is tender and most liquid is absorbed. Avoid lifting the lid too often.
Finish with veggies: Stir in frozen mixed vegetables. Cover and cook 3–5 minutes more, until the veggies are heated through and the rice is fluffy.
Optional cheesy top: Sprinkle cheese over the skillet, cover for 1–2 minutes to melt.
Taste and serve: Adjust salt and pepper.
Garnish with parsley or green onions, then serve hot.