Preheat oven to 400 degrees F.

Wash and Prick potatoes all over with a fork and rub with oil; season generously with salt and pepper.

Wrap potatoes in heavy-duty aluminum foil, and place on a rimmed baking sheet. Bake at 400 degrees for 1 ½ hours, or until potatoes are fork-tender. Remove from oven, and let stand until potatoes are cool enough to handle. Remove and discard foil.

Cut top one-third off each potato lengthwise, discarding tops. Using a melon baller or a spoon, scoop out potato pulp, leaving a ¼ inch thick shell. Place pulp in a large bowl. Place potato shells on rimmed baking sheet.

Add sour cream, cheese, melted butter, milk, bacon, parsley, minced garlic, and salt to potato pulp. Using a potato masher, mash until desired consistency is reached.

Fill potato shells evenly with potato mixture. Return to oven, and bake for 25 to 35 minutes, or until potatoes are hot. Garnish with bacon and green onion if desired.