One day to 8 hours before making, boil potatoes whole in a large stockpot over medium-high to high heat. Do not remove the skins.
Potatoes are cooked when a fork slides through the middle easily. Drain and allow to cool before refrigerating for at least 4 hours.
Cook bacon in a large skillet over medium heat until well browned on both sides. Remove and set on paper towels to drain. Reserve 3 tablespoons of bacon grease.
Peel cold potatoes, removing eyes and bad spots. Cut into 1-1 1/2-inch pieces. Add the potatoes to a large mixing bowl. Pour reserved bacon fat over potatoes and crumble bacon on top. Add remaining ingredients, except scallions.
Using a large, sturdy spoon, stir until all ingredients are well distributed throughout your potatoes. Best if covered and refrigerated overnight.
