OVEN:

Heat oven to 350°F (180°C) and position racks in top and bottom thirds. Wash potato (or potatoes) thoroughly with a stiff brush and cold running water. Dry, then using a standard fork poke 8 to 12 deep holes all over the spud so that moisture can escape during cooking. Place in a bowl and coat lightly with oil. Sprinkle with kosher salt and place potato directly on rack in middle of oven. Place a baking sheet on the lower rack to catch any drippings.

Bake 1 hour or until skin feels crisp but flesh beneath feels soft. Serve by creating a dotted line from end to end with your fork, then crack the spud open by squeezing the ends towards one another. It will pop right open. But watch out, there will be some steam.

MICROWAVE:

Scrub the potato, and prick several time with the tines of a fork. Place on a plate.

Cook on full power in the microwave for 5 minutes. Turn over, and continue to cook for 5 more minutes. When the potato is soft, remove from the microwave, and cut in half lengthwise.

Top as desired, keeping in mind that some toppings (e.g. butter) will significantly increase the calories of this dish, while others (e.g. salt, pepper, other seasonings) have little to no calories.