In a large skillet, heat the olive oil over medium heat. Add the diced onion and sauté until translucent, about 3-4 minutes.
Add the minced garlic and cook for an additional 1 minute until fragrant.
Add the ground beef to the skillet, breaking it apart with a spoon. Cook until browned, about 5-7 minutes. Drain excess fat if necessary.
Stir in the diced tomatoes (with juice), beef broth, Italian seasoning, salt, and pepper. Bring the mixture to a simmer.
Add the orzo pasta to the skillet, stirring to combine. Cover and cook for about 10-12 minutes, or until the orzo is tender and has absorbed most of the liquid, stirring occasionally.
Once the orzo is cooked, remove the skillet from heat and sprinkle the shredded mozzarella cheese on top. Cover for a few minutes until the cheese melts.
Garnish with fresh parsley before serving.