Start by roughly chopping both the black olives and pimiento-stuffed green olives. Slice green onions thinly. This step ensures that every bite of bread has a balanced mix of flavors.
In a large mixing bowl, combine the butter, mayonnaise, grated cheese, chopped olives, and green onions. Stir everything until evenly combined. I love using my hands to gently press the mixture together—it makes it easier to spread later.
Slice your French bread lengthwise and evenly spread the olive-cheese mixture on top. Bake at 350°F for 20-25 minutes or until the cheese is melted and lightly browned. The aroma while baking is irresistible!
If you want, you can refrigerate the mixture for up to two days and use it as a dip. It pairs wonderfully with crackers or fresh vegetables.