Preheat the oven to 375 degrees F and line a baking sheet with parchment paper. Pierce the potatoes in a few places with a fork; place on a microwave-safe plate and microwave, turning halfway through, until tender, about 16 minutes. Set aside until cool enough to handle.
Meanwhile, cook the bacon in a large nonstick skillet over medium heat, turning occasionally, until crisp, 9 to 11 minutes. Drain on paper towels, reserving the drippings. Roughly chop 4 slices and break the other 2 slices in half; set aside.
Slice off the top 1/4 inch of the potatoes lengthwise. Scoop the flesh from 3 potatoes into a medium bowl, leaving a 1/4-inch-thick shell. Repeat with the remaining potato but discard the flesh. Add 2 tablespoons of the reserved bacon drippings and the warmed milk to the bowl and mash with a potato masher or fork until smooth. Stir in the cheese, scallions, parsley, chopped bacon, 1/2 teaspoon salt and 1/4 teaspoon pepper.
Season the inside of the potato skins with salt and pepper. Divide the filling among the skins, then press the back of a spoon down the center of the filling to create a long, deep well. Brush the outside of the skins with the remaining bacon drippings and transfer to the baking sheet.
One at a time, crack an egg into a ramekin or teacup, then carefully pour into each potato (it's OK if some of the egg white overflows). Transfer to the oven and bake until the whites are set, 20 to 25 minutes. Season with salt and pepper and top with more scallions and the halved bacon strips.