01 -
Start cooking the bacon in a cool pan over medium heat. Once crunchy, move to a plate with a paper towel—leave the grease behind.
02 -
Take the bread and spread pesto across each piece. Layer on the mozzarella, then the tomato slices, then bacon (if you're using it). Finish by placing another bread slice on top, pesto side in.
03 -
Preheat your skillet to medium. Butter the outside of the sandwiches and put them in the pan, butter touching the skillet first. Cook 3-4 minutes ’til they’re golden brown underneath.
04 -
Spread butter on the uncoated side, flip them over, and cook another 2-3 minutes. The bread should crisp up, and the cheese will get nice and melty. Let cool for a minute or two before slicing.