Cut out nine medium-sized dough rounds to make the crust. Fit the rounds into the prepared pan.
In a medium bowl, mix 1 1/4 cups chopped spinach with the ricotta cheese, Parmesan, salt, and egg. Stir well to combine.
Fill each with cheese and spinach mixture and top them with the rest of the chopped spinach.
Sprinkle the shredded mozzarella cheese over the top.
Bake the ricotta tarts for approximately 20 minutes or until golden brown.