Grandma's Potato Salad

I don't know what Grandma created this recipe, but this Grandma is keeping it. It's not a quick and easy recipe by any means, but so worth it. Plan on people going back for seconds on this one. Make extra dressing or use less potatoes, as it absorbs into the potatoes. 

DO NOT MAKE ANY SOONER THAN THE DAY BEFORE SERVING.

5 pounds medium red potatoes

DRESSING:

1 cup water

1/2 cup butter, cubed

1/4 cup white vinegar

2 large eggs

1/2 cup sugar

4-1/2 teaspoons cornstarch

3/4 cup heavy whipping cream

3/4 cup Miracle Whip

SALAD:

1 small onion, finely chopped

2 green onions, sliced

1 teaspoon salt

1/2 teaspoon pepper

3 hard-cooked large eggs, sliced

Paprika

Place potatoes in a stockpot and cover with water. Bring to a boil. Reduce heat; cover and cook for 15-20 minutes or until tender. Drain. When cool enough to handle, peel and slice potatoes; cool completely.

For the dressing:

In the top of a double boiler or metal bowl over barely simmering water, heat water, butter and vinegar until butter is melted. In a small bowl, beat eggs; add sugar and cornstarch. Add to butter mixture; cook and stir for 5-7 minutes or until thickened. Transfer to a large bowl; cool completely.

In a small bowl, beat cream until stiff peaks form. Stir Miracle Whip into cooled dressing mixture; fold in whipped cream. Stir in onion, green onions, salt and pepper. Add potatoes; toss lightly to combine. Refrigerate, covered, until chilled.

To serve, top with hard-cooked eggs; sprinkle with paprika.

Note: 
Good if made the day before serving, but no more than that as the dressing will alter. Can make it in the morning to serve at dinner. Also, everytime I've made this I've had to add more dressing before serving. So either increase the amount of dressing you make, or reduce the amount of potatoes.