1. Preheat the oven to 425°F and lightly grease a large baking sheet or line it with parchment paper.

2. Add the ground beef and diced onion to a large skillet over medium heat. Cook until the beef is browned and the onion is soft, breaking the meat into small crumbles as it cooks. Drain excess grease if needed.

3. Stir in the garlic, taco seasoning, tomato paste, salt, and black pepper. Cook for 1 minute until fragrant.

4. Pour in the beef broth and stir well. Let the mixture simmer for 2 to 3 minutes until slightly thickened and most of the liquid is absorbed.

5. Remove the skillet from the heat and stir in the cheddar cheese, Monterey Jack cheese, and chopped cilantro. Let the filling cool for 5 minutes.

6. Warm the corn tortillas until flexible by microwaving them in a damp paper towel or heating them briefly in a skillet.

7. Spoon about 2 tablespoons of filling onto each tortilla near one edge, then roll tightly. Place each taquito seam-side down on the prepared baking sheet.

8. Brush or lightly spray the tops with olive oil.

9. Bake for 15 to 20 minutes until the taquitos are crisp and golden brown.

10. Let them cool for a few minutes, then serve hot with salsa, sour cream, guacamole, or pico de gallo.