Spread 1 side of bread slices with plain mayonnaise. (bonappetit.com)
Sprinkle on salt and freshly ground pepper, then lay the remaining bread slices on top and press down gently with the palm of your hand. (inerikaskitchen.com)
Once the oven has reached 450 °F, place a tray of bread slices in the oven on the top rack. (aggieskitchen.com)