2 tbsp olive oil
400g lean ground beef
1 large shallot, finely chopped
3 cups marinara sauce, divided
14 dried manicotti pasta tubes (225g)
1 (450g) container full-fat ricotta cheese
2 cups shredded mozzarella cheese, divided
1/2 cup finely grated Parmesan cheese, divided
1/2 cup chopped fresh parsley leaves, divided
1 large egg, lightly beaten
1 teaspoon kosher salt
Heat the oil in a large skillet over medium-high heat until shimmering. Add the ground beef and cook until the meat begins to brown, about 5 minutes. Add the shallot, cook until the shallot is translucent and the beef is cooked through, about 5 minutes more. Transfer to a large bowl and set aside to cool to room temperature.
Heat the oven to 375F/190C and prepare the baking dish. Meanwhile, bring a large pot of heavily salted water to a boil. Lightly grease a 9×13-inch baking dish with cooking spray or olive oil. Spread half of the marinara sauce in the bottom of the dish and set aside.
Add the manicotti to the water and boil until they are al dente, about 8 minutes. Drain and set aside.
Combine the ricotta, half of mozzarella, half of the Parmesan, half of the parsley, the egg, and the salt with the cooled beef mixture and stir to combine well.
Transfer the beef and cheese mixture to a piping bag or gallon size ziptop bag. Snip off a 1/2-inch hole in one bottom corner of the bag, then pipe the filling into each manicotti tube. Nestle each filled manicotti in the sauce, packed them tightly together in a single layer.
Pour the remaining marinara sauce evenly over the manicotti and sprinkle with the remaining mozzarella and Parmesan.
Bake uncovered until the sauce is bubbly, the cheese is browned, and the noodles are very tender, 35 to 40. Let cool for about 10 minutes before serving. Sprinkle with the remaining parsley just before serving.