Preheat the oven to 400F. Wash and pat dry the potatoes, and then use a sharp paring knife to poke a few holes in each. Place the potatoes directly onto a rack in the center of the oven. Bake until a fork inserted into the center easily goes in and slides back out, about 40 to 45 minutes. Cool until the potatoes aren’t too hot to handle, then cut each in half and scoop out the inside, leaving the skins about ¼-inch thick.
Turn the oven down to 375F and brush a little olive oil on the inside of a 9 by 13-inch casserole dish.
Heat 1 tablespoon olive oil in a medium skillet over medium heat; add the onion and cook until softened and starting to take on a bit of color, about 5 minutes, stirring occasionally. Add the jalapeno, garlic, salt, and pepper, and cook 1 minute more, stirring constantly. Cool slightly.
Toss the onion mixture together with the cheddar shreds, mozzarella shreds, and bacon in a medium bowl.
Arrange the potato skins in the prepared casserole dish and fill each with the onion/cheese mix.
Cover the dish with foil and bake until the cheese is melted, about 25 to 30 minutes. Sprinkle the scallion on top and serve warm.
Notes
You can store these potato skins in an airtight container in the fridge for up to 3 days.
To reheat, place the potato skins on a baking tray and reheat in a preheated 375F oven until warm, about 8 to 12 minutes.
Vegetarian Version: Omit the bacon and add ½ teaspoon smoked sweet paprika.
Lactose Free Version: Use GO Veggie! shreds instead of cheddar and mozzarella.