Beef stuffed shells is a hearty casserole dinner made with cheese stuffed shells and a meaty tomato sauce. It's topped with extra cheese and baked in the oven until bubbly.
Preheat oven to 350℉. Lightly grease a 9x13 casserole dish and set aside.
In a pot of salted boiling water, cook jumbo shells to 1 minute shy of al dente according to package directions. Drain and rinse with cold water until shells are easy to handle.
While shells are cooking, prepare filling. In a sauté pan over medium heat, add olive oil. Add onions and cook until browned around the edges, about 3 to 4 minutes. Add garlic and cook an additional 30 seconds.
Crumble ground beef into pan. Use a spatula to break up the beef into small crumbles while cooking. Cook beef until browned and cooked through.
Remove pan from heat and add marinara sauce. Stir to combine and set aside.
To a bowl, add ricotta, 1 ½ cups of the mozzarella cheese, parmesan cheese, egg, Italian seasoning, garlic powder, salt, and pepper. Mix until combined.
Pour about half of the meat sauce mixture into your prepared 9x13 dish and spread into an even layer. Set aside.
Gently fill each shell with ricotta mixture and place in rows in the baking dish. Cheese can be spooned in, or transferred to a plastic zip top bag for mess-free piping.
Pour remaining meat sauce on top. Sprinkle with reserved mozzarella cheese.
Bake, uncovered, for 30 minutes, or until cheese is melted across the top and casserole is bubbling around the edges.
Notes
Leftovers: Leftover stuffed shells will keep for 3 to 4 days in the refrigerator or up to 3 months in the freezer.
Freezing: Freeze casserole whole or portion cooked leftovers into individual serving containers. To thaw, transfer to the freezer to thaw overnight. Leftovers reheat well in the microwave. Whole casserole can be reheated in the oven at 350F for about 15-20 minutes.