Preheat your oven to 375°F (190°C).

In a large skillet, heat a tablespoon of olive oil over medium heat. Add the chopped onion and cook until it becomes soft and translucent, about 5 minutes.

Add the minced garlic to the skillet and sauté for another minute until fragrant.

Increase the heat to medium-high and add the ground beef, breaking it apart with a spoon. Cook until browned, about 7-10 minutes.

Stir in crushed tomatoes, tomato paste, beef broth, oregano, salt, and pepper. Reduce heat to low and let the ragu simmer for 20-25 minutes, stirring occasionally.

While the ragu simmers, cook the rigatoni according to package instructions in a large pot of salted boiling water until al dente.

Drain the rigatoni and return it to the pot. Pour in half of the ragu and mix until the pasta is evenly coated.

In a greased baking dish, layer half of the rigatoni mixture. Top with half of the remaining ragu and sprinkle a cup of mozzarella cheese evenly over this layer.

Add the remaining rigatoni on top, followed by the rest of the ragu, and finish with the remaining mozzarella and Parmesan cheese.

Cover the baking dish with aluminum foil and bake for 20 minutes. Remove the foil and bake an additional 15-20 minutes until golden and bubbly.

Let the baked rigatoni rest for 10 minutes after removing it from the oven, then garnish with fresh basil leaves before serving.