First, let me say that I used my cast iron griddle to make this sandwich and weight it down with a cast iron skillet and my cast iron dutch oven. The heavier the better. Just be careful that you keep sandwich in tact when going to flip it as the butter will stick from top bread to whatever you're weighing it down with.
This can also be made on a grill or Panini press.
First, Get your skillet or griddle warming. I coat with oil as well.
Butter the 2 slices of bread on one side each.
On one un buttered side. Start by laying 2 slices of American cheese side by side. Top with folded slices of turkey - evenly across the bread.
Next, spread out the tomato slices, salt & pepper.
Add the onion.
Next the provolone cheese, then folded ham slices.
Top with Swiss cheese ( I used shredded ) and other slice of bread, buttered side up. ( When I use bacon I place it on top of the Swiss cheese.)
Carefully place into hot griddle. Weight down with whatever you have heavy, being careful to balance the weight equally, so not to fall off. Continue cooking until golden on the bottom.
With a wide spatula, carefully flip the sandwich to the other side and weight it as well. Continue for roughly another 5 minutes. When is golden and cheese is melted, remove from pan to a cutting board. Slice in half and serve with your favorite spread.