In a large pot, bring salted water to a rolling boil over high heat. Add penne pasta and cook according to package instructions until al dente, around 8-10 minutes. Reserve ½ cup of cooking water, drain the rest, and set aside.

In a large skillet, heat a splash of olive oil over medium-high heat. Add the lean ground beef, breaking it up with a spatula. Sauté for 6-8 minutes until browned, then drain excess fat.

Push the browned beef to one side of the skillet and add diced onion and minced garlic to the space. Sauté for 2-3 minutes until onion is translucent.

Stir in a spoonful of tomato paste with the beef and aromatics, mixing well. Cook for 1-2 minutes to intensify flavors.

Pour in the beef broth, stir to combine and scrape up any browned bits. Bring to a simmer for 3-5 minutes until slightly thickened.

Lower the heat and mix in Greek yogurt and shredded cheese until creamy. Gradually add reserved pasta water if sauce is too thick.

Add the cooked penne pasta to the skillet, tossing gently to coat with the sauce. Season with salt and pepper to taste.

Spoon the pasta into bowls, garnishing with parsley. Serve warm.