First, bake the potatoes. Preheat the oven to 450ºF. Run the potatoes under cold water to remove any residue and pat them dry. Drizzle and season each potato with olive oil (about 1 teaspoon per potato) and 1/8 teaspoon of salt. Tightly wrap each potato with foil. Bake for about 50-60 minutes, until the potatoes are easily pierced with a fork.
While the potatoes are baking, heat the remaining 2 tablespoons of olive oil in a large skillet over medium/high heat. When the oil is fragrant, add the onion and garlic and sauté for 2-3 minutes. Remove from skillet and set aside.
To the same hot skillet, add the bacon pieces. Sauté until the bacon is fully cooked but not crispy, about 7-10 minutes. Use a paper towel to remove any excess bacon grease and set the bacon aside.
Once the potatoes are baked, unwrap the foil and let them cool for 10 minutes and reduce the oven temperature to 375ºF. Slice the warm potatoes in half (hotdog style) and carefully hollow out the insides with a tablespoon scoop. Place the potato flesh into a large bowl. Keep the skin of the potato intact with about 1/4-inch of flesh so they are sturdy enough to hold the mashed potato mixture. You should have 8 total potato skins.
To the large bowl with the potato flesh, add the butter, beef broth, and Greek yogurt. Mix to combine using a spoon, potato masher, or hand mixer (the mixture should be really mashed). Add the sour cream, 2/3 cup of cheddar cheese, sautéd onions and garlic, cooked bacon pieces, remaining salt, pepper, and red pepper flakes to the bowl and mix well.
Spoon the potato mixture evenly into the 8 potato skins.
Spray a baking sheet with nonstick cooking spray (or line a baking sheet with foil and spray the foil with nonstick cooking spray). Place all 8 of the filled potato skins onto the baking sheet.
Bake at 375ºF for 15 minutes.
Remove the potatoes from the oven, sprinkle with the remaining cheddar cheese, and bake for another 5 minutes to melt the cheese.
Let the potatoes cool for a few minutes, top with all of your favorite toppings, and enjoy!