Tip: If olives are too salty, soak them in the cold water for 15-20 minutes and then drain.
Place butter into a mixing bowl. Add mayonnaise and mix well. Add cheese, olives and green onions. Stir together until thoroughly combined.
Slice the bread in half lengthwise (you can then cut each piece in half crosswise, they fit on a baking sheet that way).
Preheat oven to 325 degrees F. Spread each piece of bread generously with the olive mixture (spread it all the way to the edges too).
Note: bread can be refrigerated or frozen at this point until you're ready to serve it.
Bake for 25 to 30 minutes or until cheese is melted and browned. Cut into slices and serve.