– 1 pound lean ground beef – 1/2 cup finely chopped onion – 1 (24 ounce) jar prepared marinara sauce – 4 teaspoons kosher salt, divided – 3/4 teaspoon freshly ground black pepper – 1 teaspoon garlic powder – 1 teaspoon Italian seasoning – 1 (12 ounce) package jumbo pasta shell – 1 cup ricotta cheese – 1/2 cup grated Parmesan cheese, divided – 2 cups shredded mozzarella cheese – 2 tablespoons finely chopped fresh parsley (optional)
Bake for 15 minutes in the preheated oven until slightly brown around the edges and bubbly inside. Let stand 10 minutes before serving. Sprinkle parsley if desired.