Thoroughly wash potatoes. Do not peel. Set aside. Add 2 cups of water to a large sauce pan. Stir in salt. Add washed potatoes. Add more water to cover.
Simmer over medium-high heat until fork tender and potatoes break easily. If they are hard, boil 5-10 minutes longer.
While potatoes are simmering, prepare frozen peas and carrots according to instructions on package. Avoid overcooking (will become mushy). Drain and set aside.
Rinse fork-tender potatoes in cold water. Cool 15-20 minutes. Peel. Place cooled potatoes into a medium-sized bowl. Mash until smooth.
Add 3 chopped/hard boiled eggs, chopped onions, and sweet relish, Add mayonnaise (or Miracle Whip) one tablespoon at a time until satisfied with creamy texture. Add mustard until satisfied with taste. Season with salt. Stir together. Set aside.
Slice remaining 7 hard boiled eggs in half. Remove egg yolks and add to potato salad (or refrigerate for another use).
Place about 1/2 tablespoon of mashed potato salad into center of each sliced egg white. Add more or less as preferred.
Before serving, garnish each stuffed egg with crumbled French fried onions and/or shredded Monterey jack cheese.