In a large skillet over medium-high heat, add the ground beef and chopped onion. Cook until the beef is no longer pink and the onion is translucent, about 6–8 minutes. Drain excess fat if needed.

Stir in garlic, cumin, smoked paprika, chili powder, oregano, salt, and pepper. Sauté for 1 minute until fragrant.

Add diced tomatoes and let the mixture simmer 2–3 minutes to meld flavors.

Remove from heat and fold in shredded cheese and cilantro.

Lay a tortilla flat, spoon 1/3 to 1/2 cup of beef and cheese mixture near the center. Fold the sides in, then roll tightly from the bottom to form a sealed package.

For frying: Heat 1/2 inch oil in a nonstick skillet over medium heat. Place chimichangas seam-side down first, turning to brown all sides, about 2–3 minutes per side.

For baking: Preheat oven to 400°F (200°C). Place chimichangas seam-side down on a baking sheet lined with parchment. Brush or spray lightly with oil. Bake 20–25 minutes until golden and crisp, flipping once for even color.

Let rest 2 minutes before cutting. Serve while hot.