Cook the bacon until crispy and set aside on paper towel
Butter one side of each slice of bread, sprinkle the cheese onto the unbuttered side of one of the slices of bread followed with guacamole, bacon, and the remaining cheese and finally top with the other slice of bread with the buttered side up.
Grill over medium heat until golden brown and the cheese is melted, about 2-3 minutes per side.