Step 1

Preheat your waffle iron or panini maker according to manufacturer's instructions.

Step 2

Spread the top of one piece of bread with mayonnaise and Dijon. Arrange 3 pieces of the ham on the bread, top with 1 piece of the provolone cheese, half of the arugula, the onions, the other half of the arugula, last piece of cheese, and the remaining 3 slices of cheese. Finally, spread the remaining piece of bread with more Dijon and mayonnaise and put that side down on top of the sandwich. Generously butter the top of the bread.

Step 3

Open the waffle iron, hold the sandwich together and carefully invert it so the buttered top is facing down on the waffle iron. Quickly butter the piece of bread that is now on the top and close the waffle iron. You may need to weight the top of the waffle iron down until the sandwich begins to compress. A heavy pan or can of something that will not be damaged by heat is a good bet.

Step 4

Toast until the sandwich is compressed and the outside is a crispy, deep golden brown. In my waffle maker, set on high, that took about 5 minutes.

Step 5

Use tongs or a spatula to carefully remove the sandwich from the waffle iron and transfer it to a cutting board. Cut in half (or quarters) and serve hot.