Slice the Italian loaf lengthwise, creating two halves. Gently hollow out some of the soft bread inside, leaving about a ½-inch border all around to hold the filling. Save the removed bread bits for another use.
In a mixing bowl, combine the softened cream cheese, sour cream, and mayonnaise until smooth. Stir in the drained and chopped artichokes, thawed spinach, Ranch seasoning mix, salt, and black pepper. Mix until everything is well incorporated and creamy.
Fold in half of the shredded mozzarella cheese into the spinach-artichoke mixture to ensure a cheesy, melty filling inside the bread. Reserve the other half of the mozzarella for topping later.
Spoon the filling evenly into the hollowed-out Italian loaf halves, pressing lightly to fill all the crevices. Distribute it well for every bite to be packed with flavor.
Brush the melted butter generously over the exposed bread edges and the top of the filling. Then sprinkle the remaining mozzarella cheese over the filled bread for a golden crust once baked.
Place the stuffed bread halves on a baking sheet and bake at 375°F (190°C) for about 20-25 minutes, or until the cheese is melted, bubbly, and starting to brown. Keep an eye on it to avoid burning.
Remove from the oven and let cool slightly before slicing into thick pieces. Serve warm for the ultimate cheesy, creamy experience.