3 Tbs. pesto
4 slices crusty white sandwich bread
5 oz. fresh mozzarella cheese, cut into 8 thin slices
1 small roasted red pepper in vinegar, halved
grilled chicken breast, cut into 6 slices (about 5 oz. total)
6 oz. arugula, stems removed
3 Tbs. unsalted butter, at room temperature
Prepare the sandwiches:
Spread the pesto on one side of the bread slices. For each sandwich, layer 2 mozzarella slices; half each of the roasted red pepper, chicken and arugula; and 2 more mozzarella slices.
Refrigerate the sandwiches:
Spread the outside of the sandwiches with the butter. Put the sandwiches on a sheet of waxed paper and refrigerate until the butter is firm, about 20 minutes.
Cook the sandwiches:
Preheat a ridged fry pan or grill pan over medium heat until hot. Place the sandwiches in the pan and weight down with a second fry pan. Cook until the undersides are golden, about 2 1/2 minutes. Turn the sandwiches over, weight them down again and cook until golden on the other side, about 2 1/2 minutes more. Alternatively, cook the sandwiches using an electric panini press according to the manufacturer’s instructions.
Transfer the sandwiches to a cutting board, cut in half and serve immediately.