Heat oil over medium-high heat. Add beef and onion and brown the beef, breaking it up with the back of a spoon, until it is no longer pink. About 7 minutes.
Drain excess fat off of the beef if necessary.
Season the beef with salt, pepper, chili powder, cumin, oregano, and add the tomato paste. Toss to coat evenly.
Add the pasta, the can of diced tomatoes + jalapenos, and the broth (or milk if using). Stir to combine.
Bring to a boil, then adjust heat to a slow steady boil, stirring occasionally and cook pasta for 13 minutes.
Turn off heat and stir in cheese (if using).
Let stand a few minutes before serving.
Garnish (optional) with freshly chopped cilantro, sliced avocado, sliced jalapeños, and radishes.