1Cook shells according to package directions.
Drain and set aside.
Heat cooking oil spray in a large skillet. Add onions and cook until softened. Add spinach and cook until wilted.
2Press out excess moisture. Add seasoned salt.
Combine ricotta, breadcrumbs, parmesean cheese and nutmeg. Add the spinach and mix gently.
3Stuff each of the shells evenly with the ricotta mixture.
Spread 1 cup of the marinara sauce in the bottom of a 13x9 baking dish.
Arrange the shells in a single layer. and put a spoonful of the remaining sauce on each shell.
4Bake until the top is golden and the shells are heated (about 30 minutes at 375')