In a small bowl, whisk together the melted butter, the egg, and pepper. Brush this mixture all over the sliders.
⅓ cup salted butter, 1 egg, ½ teaspoon pepper
Bake for 25 minutes or until the cheese is melted and the buns are toasted. If the buns start turning too brown, cover them loosely with tented tin foil. (We don’t want it to stick to the buns.)
Sprinkle the tops with powdered sugar and serve with jam on the side if desired.