Kosher salt and freshly ground black pepperto taste
4slicessourdough bread
2tablespoonssalted butterat room temperature
3ouncesswissgrated
3ouncesextra-sharp cheddargrated
Instructions
Combine the mayonnaise, mustard, and parmesan. Season with salt and pepper to taste. Spread one side of bread slices lightly with butter. Flip the slices and spread the other side generously with the mayonnaise mixture. Don't neglect the corners!
Pile 1/3 cup grated cheese evenly on top of the mayonnaise blend. Top with a second slice of bread, mayonnaise blend down.
Meanwhile, heat an electric panini press. When the press is hot, cook the sandwiches for 3 to 5 minutes in batches until the bread is toasted and the cheese is melted. Allow to cool for 2 minutes. Cut in half and serve warm.