Spinach and Ricotta-Stuffed Shells

2 cups Basic Marinara, divided
Cooking spray
2 1/2 cups part-skim ricotta cheese
1/2 cup (2 ounces) grated fresh Parmesan cheese
1/2 teaspoon onion powder
1/2 teaspoon dried oregano
1/4 teaspoon salt
1/4 teaspoon freshly ground black pepper
1 (10-ounce) package frozen chopped spinach, thawed, drained, and squeezed dry
1 large egg yolk
1 garlic clove, minced
24 cooked jumbo pasta shells

Preheat oven to 350°. Spread 1/2 cup Basic Marinara over bottom of a 13 x 9-inch baking dish coated with cooking spray. Combine ricotta and next 8 ingredients (through garlic) in a large bowl, stirring well.

Spoon about 1 1/2 tablespoons filling into each pasta shell. Arrange stuffed shells in prepared dish; spread with remaining 1 1/2 cups Basic Marinara. Cover and bake at 350° for 30 minutes. Let stand 5 minutes before serving. Makes 6 servings