Created by Mikekey on January 20, 2016
Step 1: Place eggs in a large saucepan; add water to cover by 1". Bring to a boil, cover, and remove from heat. Let sit for 10 minutes. Drain. Transfer eggs to a bowl of ice water and let cool completely, about 10 minutes; peel. Halve lengthwise and remove yolks.
Step 2: Coarsely chop bacon. Cook in a medium skillet over medium heat until browned and crisp. Transfer bacon to paper towels. Strain drippings through a fine-mesh sieve into a small bowl. Add melted butter if needed to measure 2 Tbsp.
Step 3: Finely mash reserved yolks, bacon fat (and/or butter), mayonnaise, mustard, and chopped scallions in a medium bowl; season with salt and freshly ground black pepper.
Step 4: Transfer to a large resealable freezer bag, then cut 1/2" off 1 corner.
Step 5: Pipe into whites; garnish with thinly sliced scallions and reserved bacon.
Step 6: Store in refrigerator until ready to serve.