Roll out dough to 1/8-inch thick with a rolling pin. If the dough sticks to the pin, either the plantain was too ripe or the dough isn't chilled enough. To fix this, place a piece of parchment or plastic wrap between the pin and the dough and continue to roll. Once the dough is the desired thickness, remove the parchment paper or plastic wrap on top of the rolled out dough and discard before baking.
Place dough in oven for 3-4 minutes. Remove from oven and use a pizza cutter to cut dough into desired size and shape. Sprinkle with additional salt, if desired.
Return to oven and continue to bake for an additional 15 to 20 minutes or until desired crispness is achieved. As they bake, crackers will begin to pull away from each other on the baking sheet.