Stuffed Shells with Marinara

Preheat oven to 375°. Cook shells in a large pot of boiling salted water, stirring occasionally, until very al dente; drain. Run under cold water to stop the cooking and drain again.

Lightly whisk egg yolks and egg in a large bowl. Stir in ricotta, Parmesan, parsley, and 1½ cups mozzarella; season with salt and pepper. Transfer filling to a large resealable plastic bag.

Spread 1½ cups marinara sauce in a 13x9" baking dish. Snip off 1 end of plastic bag and, working one at a time, squeeze filling into shells, arranging them in a single layer in baking dish as you go. Top with remaining 1½ cups marinara sauce and remaining mozzarella. Cover pan tightly with foil and bake shells until sauce is bubbling throughout, 35–40 minutes. Let rest 5 minutes.

Carefully move rack to top of oven and heat broiler. Uncover pasta and broil until lightly browned on top, about 2 minutes. Sprinkle with oregano and more Parmesan and drizzle with oil. Do Ahead: Pasta can be baked 3 days ahead. Let cool; cover and chill. Reheat, covered, at 375°.