Whisk the raw eggs and sugar in a pan over very low heat. I quite like using a large skillet for this step. Add the cornstarch and vinegar and whisk to combine. Increase to medium heat and continue cooking until thickened. You may also use 1/2 cup apple cider vinegar instead of distilled white vinegar.
2 extra large eggs, ½ cup white sugar, 1 teaspoon corn starch, ½ cup white vinegar
Add the evaporated milk, mustard, and butter, whisking each ingredient thoroughly before adding the next. Once homogeneous, remove from the heat.
5 ounce can evaporated milk, 1 teaspoon prepared mustard, ¼ cup salted butter or ghee
Season the dressing with salt and black pepper and scrape into a large measuring cup or other vessel. Removing from the heat AND removing from the hot pan will cease the cooking process. Set aside. The dressing will cool slightly while you work the potatoes.
Kosher salt, black pepper
Boil potatoes until fork-tender, then drain and transfer to a large bowl. Mash about half with a potato masher, leaving some larger chunks intact. Gently combine for a balanced mix of creamy and chunky textures.
6 medium red potatoes
Finish the dressing by whisking in the mayonnaise until smooth. To the potatoes, add chopped boiled eggs, onion, celery, salt, and black pepper. Mix gently to combine.
Kosher salt, 1 cup mayonnaise, 1 medium yellow onion, 1 cup chopped celery, 6 hard cooked eggs, black pepper
Pour the (still) warm dressing over the hot potato mixture and mix thoroughly. Cover with plastic wrap. Chill until thickened and set, at least two hours, 24 hours preferably.
Uncover and stir the mixture well. TASTE. Season as needed. It is now that I add chopped celery leaves and additional black pepper and stir again. Garnish with intact celery leaves, gem lettuces, and cherry tomatoes for presentation.
1 cup chopped celery