Rub potatoes with olive oil and sprinkle with salt. Place on a baking sheet and bake until tender, about 1 hour. Let cool. Slice in half lengthwise then scoop out the potato filling; discard or use in another recipe.
Remove from oven and spoon in some marinara sauce. Top with mozzarella cheese and mini pepperoni slices.
Bake for 5-7 minutes, or until cheese is gooey. Remove from oven and sprinkle with desired garnish. Serve immediately.