For the dressing, combine olive oil, lemon juice and zest, mustard, chilli pepper, salt, black pepper, and mint leaves in a bowl or bottle with the lid. Whisk or shake nicely to combine all the ingredients.
Bring water to a boil in a large saucepan, and season it with salt. Add potatoes, bring them to a boil, and then reduce to a simmer. Cook for 5 minutes or until just cooked – don’t let them overcook or become too soft.
Transfer boiled potatoes to a colander and drain all the water. Allow them to cool.
Transfer potatoes to a mixing bowl. Add half of the salad dressing over the potatoes. Gently toss them.
Add finely chopped dill and parsley when ready to serve the potato salad. Add the remaining dressing, and toss.
Herbed Potato Salad is ready to serve.