Heat a greased pan over medium heat. Add the chopped spinach. Cook, stirring occasionally, until the spinach is wilted and bright green. (Alternatively, wilt the spinach for about 2-3 minutes in the microwave.) Set aside to cool. If you want to speed up the cooling process, you can place the bowl into a larger bowl containing ice (optional).

While the spinach cools, preheat the oven to 350 degrees F (177 degrees C).

Meanwhile, heat the cream cheese in the microwave or in a small saucepan on the stove over low heat. Once it melts enough to stir, add in the mayonnaise, sour cream, grated parmesan cheese, chopped artichoke hearts, minced garlic, black pepper, and half of the shredded mozzarella. Stir to combine.

When the spinach is cool enough to handle, gather it into a ball and squeeze several times, making sure to get out as much water as possible. Add the spinach to the artichoke mixture.

Transfer the dip to a small ceramic appetizer dish or large ramekin. Smooth the top with a spatula. Sprinkle the remaining shredded mozzarella on top.

Bake for about 30 minutes, until hot and bubbly. Serve warm.