Preheat the oven to 350 degrees. Cut a hole in the top of a bread bowl and scoop out the bread inside, creating a cavity for the dip. Set aside the extra bread for dipping later.
In a large bowl, combine the mayonnaise, Parmesan, mozzarella and cream cheese until smooth. Mix in the artichokes, green onions, garlic and season with salt, pepper, and cayenne. Stir well.
Dump mixture into bread bowl cavity. Cover lightly with a small piece of aluminum foil. Bake for about 15-20 minutes, until heated through. You don't want the bread to get too crispy.Top with an additional sprinkling of Parmesan cheese and serve with bread, chips, carrots, celery, or other veggie dippers.