Cook bacon until crispy. Drain, reserving a few tablespoons of the grease, and crumble. Set aside.
Place the potatoes in a large saucepan. Cover with cold water. Add a tablespoon of the bacon grease and some salt and place over medium-high heat. Bring to a boil and cook until the potatoes are tender, about 15 to 20 minutes. Drain and let the potatoes cool and then cut into bite-size pieces.
In a separate bowl, mix mayonnaise, Dijon mustard, salt, and pepper for dressing.
Toss potatoes, onion, and egg in dressing. Add bacon. Serve chilled.
This recipe was provided by professional chefs and has been scaled down from a bulk recipe provided by a restaurant. We have not tested this recipe, in the proportions indicated, and therefore, we cannot make any representation as to the results.