Wash and scrub potatoes thoroughly. Pat dry and poke each potato a few times with a fork to allow steam to escape while baking.
Rub potatoes with oil and sprinkle with salt.
Place directly on the oven rack or on a baking tray and bake for 45-60 minutes, or until potatoes are tender when pierced with a fork. Remove potatoes from the oven and let them cool slightly.
Cut potatoes in half lengthwise. Carefully scoop out the potato flesh, leaving the shell intact. Place shells on a baking tray and set aside.
In a large mixing bowl, using a potato masher or fork, mash the potato flesh.
Mix in the sour cream, milk, butter, half of the crumbled bacon, ½ cup shredded cheddar cheese, half of the chopped green onions, salt, and pepper until well combined.
Spoon the potato mixture into the shells, dividing equally between the 8 potato shells. Sprinkle filled potato halves with remaining cheese and bacon.
Place potatoes in the oven and bake for 15-20 minutes, or until the cheese is melted and bubbly.
Remove from the oven and garnish with remaining chopped green onions. Let the potatoes cool for a few minutes before serving.
Notes
Choose baking potatoes of a similar size if possible.
Leave about ¼ to ½ inch of potato on the skin so it stays firm enough to hold the filling.
Use a freezer bag with a corner snipped off to pipe the mashed potato filling into each potato shell.
Twice baked potatoes can be assembled and refrigerated up to 2 days ahead of time. They also can be assembled and frozen for a quick side dish.