Place the potatoes in a large saucepan and cover with plenty of cold water. Bring to the boil over high heat and cook for 15-20 minutes or until tender. Drain and set aside for 15 minutes to cool slightly. Cut into halves or quarters.
Use a fork to whisk together the sour cream, mayonnaise, dill, parsley, garlic, mint, mustard and lemon juice in a large bowl until well combined. Taste and season with salt and pepper.
Place the potatoes and green shallot in a large serving bowl. Spoon dressing over the potato mixture and gently toss until potatoes are well coated in dressing. Serve immediately.
You can prepare this recipe to the end of step 2 up to 1 day ahead. Place in separate bowls, cover with plastic wrap and store in the fridge. Continue from step 3, 1 hour before serving the main.