Tips. 1  You can bake multiple potatoes at the same time in a toaster oven, depending on the size of the oven. 2  Add 10 to 15 minutes cooking time when baking four or more potatoes together.aked potatoes make a satisfying side dish or main course, especially when topped with lean ground beef or reduced-fat cheese. It generally takes about an hour to bake a potato in a toaster oven, depending on the size of the potato.