Simply the Best Cold Potato Salad

I came up with this recipe for the creamiest,
richest potato salad you will ever make.
The secret is in the homemade dressing.
I get nothing but raves every time I make it.
I like to serve it on a bed of fresh lettuce.

Ingredients:
6 medium potatoes
1 small onion, finely chopped
1 cup celery, chopped
1 teaspoon salt
6 hard-cooked eggs, diced
2 eggs, beaten
1/2 cup white sugar
1 teaspoon cornstarch
salt to taste
1/2 cup vinegar
1 (5 ounce) can evaporated milk
1 teaspoon prepared yellow mustard
1/4 cup butter
1 cup mayonnaise

Directions:
Place the potatoes into a large pot,
and fill with enough water to cover.
Bring to a boil, and cook for about 20 minutes,
or until easily pierced with a fork.
Drain. Cool, peel and dice.
Transfer to a large bowl,
and toss with the onion, celery,
1 teaspoon of salt, and hard-cooked eggs.
While the potatoes are cooking,
whisk together 2 eggs, sugar,
cornstarch, and salt in a saucepan.
Stir in the vinegar, milk, and mustard.
Cook over medium heat, stirring frequently,
until thickened, about 10 minutes.
Remove from heat, and stir in the butter.
Refrigerate until cool,
then stir in the mayonnaise.
Stir the dressing into the bowl
of potato salad gently until evenly coated.
Chill several hours or overnight
before serving for best flavor.