Prep the spinach and artichoke. Preheat the oven to 350°F. Using a cutting board and sharp knife, chop the fresh spinach and set it aside. Drain the jar of artichoke hearts. Using a paper towel or cheesecloth, squeeze out any excess liquid. Chop the artichoke hearts into small pieces and set aside.
Mix everything. Add the softened cream cheese, sour cream, 5 ounces of shredded mozzarella, shredded parmesan cheese, minced garlic, red pepper flakes, salt, and black pepper to a large mixing bowl and stir until well combined. Fold in the chopped spinach and artichoke hearts. Mix until combined.
Pour the mixture into a baking dish. Transfer the mixture to an even layer in one of the following: a 9" x 9" ceramic baking dish, an 11" x 8" ceramic baking dish, or a medium-sized cast iron skillet. Top with the remaining 3 ounces of mozzarella.
Bake. Place the baking dish in the oven and bake for 25-28 minutes, or until the sides start to bubble. Broil for 1-2 minutes or until the mozzarella on top gets golden brown. Garnish with fresh parsley, and serve with tortilla chips or chopped vegetables.