Stuffed Shells with Marinara

Name: Stuffed Shells with Marinara
Ingredients: 12 ounces jumbo pasta shells; Kosher salt; 2 large egg yolks; 1 large egg; 2 cups whole-milk fresh ricotta; 3 ounces Parmesan, finely grated, plus more for serving; ¼ cup finely chopped parsley; 8 ounces low-moisture mozzarella, coarsely grated, divided; Freshly ground black pepper; 3 cups Classic Marinara Sauce, divided; Dried oregano and olive oil (for serving)