Preheat the oven to 400°F. Slice the French bread loaf lengthwise and arrange both halves cut-side up on a baking sheet.
In a mixing bowl, thoroughly blend the softened butter with garlic powder, minced garlic, and Italian seasoning until smooth. Distribute the butter mixture generously over each bread half.
Sprinkle an even layer of Colby Jack and mozzarella cheese across the top of the buttered bread.
Transfer the baking sheet to the oven and bake for 12 to 15 minutes, or until the cheese is fully melted and bubbling. For an extra crisp finish, place under the broiler for 1 to 2 minutes at the end.
Optionally, sprinkle with chopped fresh parsley before serving.