Begin by boiling salted water in a large pot. Add potato pieces and cook for 10-15 minutes until tender; drain and let cool.

In a large mixing bowl, whisk together Greek yogurt, Dijon mustard, lemon juice, olive oil, salt, and pepper until smooth.

Gently fold the cooled potatoes into the dressing, ensuring each piece is coated without breaking apart.

Add chopped red onion and fresh herbs to the potato mixture, stirring lightly until well combined.

Cover and refrigerate for at least one hour to allow the flavors to meld before serving.