Heat the BBQ grill on medium heat.
Spread softened butter on both sides of each piece of bread.
To the preheated grill, add the buttered slices of bread.
Cook until there are light grill marks on one side (about 4 minutes) then turn the pieces of bread over.
To each of the sides of the bread with the grill marks, add string cheese, blue cheese, orange zest, and sliced Gouda cheese.
Then close the lid on the BBQ until the cheese is melted and there are grill marks on the bread that is grill-side down (about 5 minutes).