Super delicious, super easy with specialty meat or leftovers from a cheese board
Preheat skillet over medium-low heat
Slice mozzarella and tomatoes into 1/4" slices. Then slice the mozzarella circles in half to fit the bread. Sprinkle with a pinch of kosher salt and let sit. I used about 1/2 teaspoon to cover both the tomatoes and the mozzarella.
Cut ciabatta, or bread of your choice, into (8) 1/2" slices. Butter one side of 4 slices of bread, if using unsalted butter then sprinkle a pinch of kosher salt over the butter. Lay the buttered side of the bread down in the heated skillet.
Build your sandwiches in the skillet. Start with the mozzarella (2 full circle slices per sandwich), then the meat (a total of 6 slices), 2-3 tomato slices and a sprinkling of shredded cheese. If you have arugula or spinach add that now. Top the pan to melt the cheese while you prepare the bread.
Butter the remaining 4 slices of bread and top the sandwiches. Add a lid to the pan to help melt the cheese.
Check the bottom piece of bread and see if it is golden brown. If it's cooking too fast turn down the heat. Flip the sandwich when the bottom piece is golden brown.
If using thin, meaning not tall oval pieces, then you will probably need a spatula and a free hand to flip the sandwich or it will fall apart.
Once flipped, put the lid back on until ready. The whole cooking time only takes about 5-8 minutes depending on your heat and the thickness of your pan.