01 -  Preheat oven to 375°F (190°C). Line a baking sheet with parchment paper. 
 02 -  With a serrated bread knife, slice loaf in a crosshatch pattern, ensuring not to cut fully through; leave approximately 1/2 inch intact at the base. 
 03 -  In a mixing bowl, combine spinach, artichoke hearts, garlic, cream cheese, Alfredo sauce, Parmesan, mozzarella, sour cream, salt, black pepper, and red pepper flakes until thoroughly blended. 
 04 -  Carefully separate bread sections and stuff the spinach-artichoke mixture deeply between slits, pressing firmly with a spoon. 
 05 -  Evenly drizzle melted unsalted butter over the filled bread. 
 06 -  Loosely wrap the stuffed loaf with aluminum foil. Bake for 15 minutes. 
 07 -  Remove foil and continue baking for 8 to 10 minutes, or until cheese bubbles and turns golden. 
 08 -  Transfer from oven, sprinkle with chopped fresh parsley, and allow to cool slightly before serving.