Heat olive oil in a large skillet over medium-high heat.
Add the ground beef and cook, breaking it apart with a spatula, until browned and cooked through, about 5-7 minutes.
Add the diced onion to the skillet and cook until softened, about 3 minutes.
Stir in the minced garlic and cook for 1 minute until fragrant.
Add the orzo pasta to the skillet and stir to combine with the beef mixture.
Pour in the diced tomatoes with their juices and the beef broth.
Add the dried oregano, dried basil, salt, black pepper, and crushed red pepper flakes. Stir well.
Bring the mixture to a boil, then reduce heat to low, cover, and simmer for 12-15 minutes, or until the orzo is tender and most of the liquid is absorbed. Stir occasionally to prevent sticking.
Remove the skillet from heat and sprinkle shredded mozzarella cheese evenly over the top.
Cover the skillet again and let it sit for 2-3 minutes until the cheese melts.
Garnish with chopped fresh parsley before serving.