This french-toast sandwich tastes great grilled at dessert time.
In a shallow bowl, whisk together egg, milk, brown sugar, nutmeg, and a pinch of salt; set aside.
Spread each slice of bread with 1 tablespoon peanut butter. Dividing evenly, sandwich banana pieces between slices of bread.
In a medium nonstick skillet, heat butter over medium. One at a time, dip both sides of sandwiches in egg mixture, and place in skillet. Cook until golden brown, 1 to 3 minutes per side.
Transfer sandwiches to a work surface. Using a serrated knife, cut sandwiches into quarters. Dust with confectioners' sugar, and serve immediately.