Poke a few holes in each potato with a sharp knife.
Bake for 40-60 minutes, or until done as desired. Cooking time depends on the size of the potatoes and how much 'crunch' you want to your salad. I use a bamboo skewer to test for doneness.
Remove potatoes from oven and let cool.
Meanwhile, in a small bowl, combine the vinegar, dried parsley and celery flakes. Set aside to let the dried herbs rehydrate, stirring every 5 minutes or so.
In a medium bowl combine the red onion, relishes and sugar.
Peel the potatoes.
Chop potatoes into cubes and add to the bowl containing the onion mixture.
Gently toss the potatoes to coat.
Gently stir in the vinegar and dried herb mixture.
Add half of the mayonnaise and stir. If you want a creamier salad add more mayonnaise.
Sprinkle with the celery salt.
Taste and add salt and pepper to taste. If you want, also add more celery salt but be careful. It's strong stuff and can quickly overwhelm the salad. I happen to like it so I added more.