Warm a skillet or frying pan over medium-heat. Butter both sides of your bread and then grill one side.
Once it has lightly browned, flip bread over to brown other side. Turn the heat to low. Then spread the pesto on the grilled side and the cheese on top.
Allow cheese to melt a little, then place tomatoes on top of the cheese followed by the top piece of bread. Turn the heat off if browning too fast and allow sandwich to sit in the skillet until melted.
Notes
Additions: A drizzle of balsamic glaze or some sliced cooked chicken would also make a delicious addition. Pesto: I love using my favorite homemade basil pesto when making this recipe.