Turn the stove to high heat right now. Bring the water to a rolling boil quickly. This starts the cooking process for the whole potatoes.

Lower the heat and simmer for fifteen minutes. The potatoes should be tender when poked with forks. Drain them in a colander and let them cool.

Cut the cool potatoes into small bite-sized chunks. Place them into your large mixing bowl very carefully. Do not mash them while you are cutting them.

Whisk the mayo, mustard, salt, and pepper together. Add the chopped herbs, onions, and celery to the mix. Stir until the dressing is very smooth and creamy.

Pour the dressing over the potato chunks now. Toss everything gently to coat each piece of potato. Chill in the fridge for one hour before serving.