Preheat the oven to 350° and lightly grease a 9×13 baking dish.
TIP: season water that pasta is cooked in to infuse it with more flavor.TIP: this recipe makes about 18 stuffed shells but cook 2-3 extra shells just in case some rip and break apart.
Cook jumbo shells pasta according to the package instructions until they are al dente. You want the shells to be just slightly under-cooked because they will finish cooking in the oven.
Once cooked, strain, and set aside to cool down enough to be handled.
While pasta is cooking, mix the filling.
Combine ricotta cheese, egg, herbs, pressed garlic, Parmesan cheese, Mozzarella cheese, and seasoning in a mixing bowl. Use a fork to mix everything well, until all ingredients are evenly incorporated throughout. (Set aside about 1/3 cup of shredded Mozzarella for topping.)
Spread about 3 cups of marinara sauce over the bottom of the 9×13 baking dish and spread it evenly.
Fill each shell with about 1.5-2 tablespoons of ricotta filling and place it in the pan.
TIP: I don’t like to place shells seam down because the filling often leaks out of the shells, so place shells in the pan seam up.
Sprinkle some Mozzarella cheese and oregano over each shell and bake for about 20-25 minutes.