1. Heat the olive oil in a large skillet over medium heat. Add the diced onion and minced garlic, sautéing until the onion becomes translucent and fragrant, about 3-4 minutes.
2. Add the ground beef to the skillet, breaking it up with a wooden spoon, and cook until browned, about 5-7 minutes. Drain any excess fat.
3. Sprinkle the taco seasoning over the beef and mix well to coat. Pour in the beef broth, diced tomatoes, and tomato sauce, stirring to combine.
4. Add the pasta shells to the skillet, ensuring they are submerged in the liquid. Bring the mixture to a simmer, cover, and cook for 15-20 minutes, or until the pasta is tender and the sauce has thickened.
5. Stir in the shredded cheddar cheese until melted and creamy. Season with salt and pepper to taste.
6. Serve hot, garnished with any optional toppings like sour cream, jalapeños, or cilantro for added flavor and flair.

Pro tip: Use the same pot for browning the beef and cooking the pasta for an easy cleanup. It’s a trick I learned during those busy weeknights when every minute counted!