This baked mostaccioli is a satisfying casserole loaded with savory ground beef, sweet Italian sausage, pasta, marinara sauce, and lots of melted, bubbly cheese!
Prep. Preheat your oven to 375°F and grease a 9×13-inch baking pan.
Cook the pasta. Bring a large pot of salted water to a boil. Cook the mostaccioli pasta according to the package instructions until it's al dente. Drain the pasta and set it aside.
Sauté the onion. In a large skillet, heat the olive oil over medium heat. Add the onion and sauté until translucent.
Brown the beef. Add the ground beef and sausage to the pan and season with salt, black pepper, garlic powder, and dried oregano. Sauté until browned and cooked through, breaking it up with a spoon as it cooks.
Make it tomatoey. Stir the crushed tomatoes and marinara sauce into the meat mixture, set the heat to low, and simmer for 10-15 minutes.
Make the ricotta filling. Whisk together the ricotta cheese, grated Parmesan, egg, parsley, garlic powder, salt, and black pepper.
Assemble. In the prepared baking dish, spread 1/3 of the meat sauce. Spread ½ of the mostaccioli pasta on top followed by ½ of the ricotta mixture. Repeat (meat sauce, pasta, ricotta mixture) and top with the remaining meat sauce followed by the grated mozzarella.
Bake. Cover the baking dish with aluminum foil and bake in the preheated oven for about 25 minutes. Remove the foil and bake the mostaccioli for an additional 15-20 minutes, or until the cheese is bubbly and golden brown.