In a pot of boiling salted water, add the cubed potatoes and cook for about 10 minutes until tender.

Add the green beans to the pot and cook for an additional 5 minutes until bright green and tender-crisp.

Drain the vegetables in a colander and rinse under cold water to stop the cooking process.

In a mixing bowl, whisk together the olive oil, apple cider vinegar, Dijon mustard, minced garlic, salt, and black pepper until well combined.

In a large bowl, combine the drained potatoes and green beans. Pour the dressing over the vegetables and toss gently to coat.

Sprinkle with chopped parsley and serve immediately or chill in the refrigerator for 30 minutes before serving.