Preheat oven to 400°. Scrub and pierce potatoes; rub each with 1 teaspoon butter. Place on a baking sheet. Bake 45-50 minutes or until tender.
Meanwhile, in a small skillet, cook bacon over medium heat until crisp. Remove to paper towels; drain, reserving 1 tablespoon drippings. In drippings, saute onion until tender; set aside.
When potatoes are cool enough to handle, cut a thin slice off the top of each and discard. Scoop out pulp, leaving a thin shell. In a small bowl, mash pulp with remaining butter. Stir in milk, egg, salt and pepper. Stir in the cheese, bacon and onion.
Spoon into the potato shells. Place on a baking sheet. Bake at 400° 15-20 minutes or until heated through.
Every editorial product is independently selected, though we may be compensated or receive an affiliate commission if you buy something through our links. Ratings and prices are accurate and items are in stock as of time of publication.