You can use either fresh or frozen spinach with this recipe. If you are using frozen spinach, make sure to thaw it completely and then drain it well. It is best to make sure all of the water is out of the spinach. I like to place the spinach between 2 clean towels with something heavy on top to press the water out. If using fresh, you will want to steam or sautee it first to cook down before adding it to this recipe. Again, remove any excess liquid from the spinach before adding it to the cream cheese stuffing mixture.