Preheat your oven to 350°F (175°C).
Cook the manicotti shells according to the package instructions. Drain and set aside.
In a saucepan, heat olive oil over medium heat. Add garlic and cook until fragrant.
Add ground beef to the saucepan and cook until browned. Season with salt and pepper.
In a mixing bowl, combine cooked ground beef, ricotta cheese, and half of the Parmesan cheese.
Stuff the manicotti shells with the meat and cheese mixture.
Spread a thin layer of marinara sauce on the bottom of a baking dish. Arrange the stuffed manicotti shells on top.
Pour the remaining marinara sauce over the manicotti shells. Sprinkle with mozzarella cheese and the remaining Parmesan cheese.
Bake in the preheated oven for 30-35 minutes, or until the cheese is melted and bubbly.
Let it cool for a few minutes before serving. Enjoy!