1/2 stick unsalted butter (1/4 cup), softened to the point of being slightly melted
1 loaf of French or Italian bread (I used Ciabatta)
Make the cheesy topping: In a small bowl, mix the butter and garlic together until smooth. In a separate large bowl, mix together the cheeses and the green onion. Stir in the mayonnaise and sour cream. Add the butter mixture to the cheese mixture.
Spread cheese over bread: Preheat broiler. Slice loaf of bread in half horizontally, lay crust side down on a foil-lined baking sheet. Spread cheese mixture over the bread.
Place under the broiler until nicely browned, about 3 to 5 minutes.
Slice: Remove from broiler and let sit for 5 minutes until cool enough to handle. Slice the bread with a bread knife. Serve.
Try mixing in other ingredients with the topping mixture, such as chopped black olives, chopped canned artichoke hearts, minced shrimp, or crab meat.