Wash the baby yellow potatoes thoroughly. In a large pot, bring salted water to a boil, then add the potatoes. Cook for 10-15 minutes until fork-tender. Drain and cool for 10 minutes.

In a mixing bowl, combine the cooled, diced potatoes with crumbled feta, sliced Kalamata olives, chopped dill, and parsley. Gently fold the ingredients together.

In a small bowl, whisk together olive oil, red wine vinegar, mustard (if using), salt, and pepper until combined.

Drizzle the vinaigrette over the potato mixture and gently toss until evenly coated.

Cover and refrigerate for at least 30 minutes to meld flavors or serve immediately. Garnish with fresh herbs before serving.