Boil 6 oz. of fresh spinach in an inch of water in a medium-sized pot for about 8 minutes. Drain, and squeeze any excess water out with a paper towel. Now, place 1 tablespoon butter in a saucepan and turn the heat on to low. Add in 4 oz. cream cheese and 1/2 teaspoon minced garlic. Cook and stir until this mixture is blended. Remove from heat, and add in the cooked spinach, an 8.5 oz. can of chopped artichoke hearts, 1/4 cup of mozzarella cheese, and 1/4 cup of sour cream. Mix thoroughly, and then pour into a pie plate (or similar oven-proof dish) that has been sprayed with cooking oil. Bake in an oven that has been preheated to 350 degrees. Turn the oven to broil, and broil for about 2 minutes, or until the top is nicely browned. Serve immediately with crisp pita chips or restaurant-style tortilla chips. Note: As soon as you put your artichoke-spinach dip in the oven, you can start preparing your pita chips, and they will be ready at about the same time!