All ingredients ready? Let's begin!
Brush a sheet pan with 1 tablespoon of olive oil and set aside.
Bring a large pot of water with kosher salt to a boil over high heat. Cook the manicotti until al-dente, approximately 5 minutes. Using a spider or slotted spoon, transfer the manicotti to the oiled baking sheet and set it aside to cool.
While the pasta is cooking, place a large skillet over medium-high heat. Add a tablespoon of olive oil to the pan along with the onion. Cook the onion until it starts to soften, about 1 minute. Add the garlic and oregano to the pan and continue to cook until the garlic and herbs are fragrant, about another 1 minute. Add the ground beef to the pan and cook, breaking it up with a spoon, until the beef is browned, approximately 4 minutes. Remove the pan from the heat and allow the beef to cool.
In a large mixing bowl, place the ricotta, 1-1/2 cups of the mozzarella, 1/2 cup of the parmesan, parsley, and basil. Stir together to combine well. Fold the cooled beef into the cheese and herb mixture.
Preheat your oven to 350°F.
Coat a glass or ceramic 9x13 inch baking dish with a tablespoon of olive oil. Spoon 1-1/2 cups of the marinara sauce into the baking dish.
Spoon the cheese and beef filling into the manicotti. Place the filled manicotti in a single layer in the baking dish on top of the sauce. Spoon the remaining sauce over the top of the manicotti. Sprinkle the remaining mozzarella over the pasta and sauce. Then, add the remaining parmesan over the mozzarella. Drizzle the last tablespoon of olive oil over the cheese.
Place the dish in the oven and bake for 30 to 35 minutes until the sauce is bubbling. Remove the dish from the oven and allow it to cool for at least 5 minutes.
Serve the pasta while warm with a green salad.