In a large bowl, pour in the cheeses, egg, and spices.
Combine the ricotta, mozzarella, parmesan, and beaten egg using a spatula until smooth.
Scoop the mixture into a large ziplock bag, then snip the bottom of the bag.
Meanwhile, Boil the shells to al dente, strain then set aside to cool for 2 minutes. Add marinara to the bottom of a large casserole dish.
Pipe the filling into each of the shells, enough to just spill out at the sides. Place the shells in a baking dish, repeat until all shells have been filled, 20 in total.
Top the shells with the rest of the mozzarella cheese. Cover with foil 375º for 25 minutes then uncover for broil: to brown the cheese 3-4 minutes.
Notes
Remember to cook the pasta just to al dente so that the shells don't fall apart when baking.Piping the filling is a whole lot easier than using a spoon or an ice cream scoop. I highly recommend using a large ziplock bag and snipping the bottom to "pipe" the filling into each shell.Don't forget to use the seasonings in the filling, this gives incredible flavor and extra color too.