Butter both sides of all 4 slices of bread using 2 tablespoons of butter.
Place a large skillet over medium high heat and melt the remaining butter.
Place the 4 slices of bread into the skillet and grill for about a minute, or until the grilled side turns golden brown.
Flip the bread and arrange 1 slice of cheese on each bread. Leave on heat until the cheese is melted and the grilled side turns golden brown.
Remove from skillet and scoop 2 spoonful of guacamole on two slices of bread.
Top them with the two slices of bread without the guacamole and cut in half before serving.