1/3 tablespoons red wine vinegar (or white wine vinegar)
1 teaspoon Dijon mustard (optional, for extra tang)
1 teaspoon dried oregano
1 teaspoon red pepper flakes ( adjust to taste )
2 tablespoons fresh parsley, chopped
Salt and freshly ground black pepper, to taste
Instructions
Cook the potatoesPlace the potatoes in a large pot of salted water. Bring to a boil and cook until just fork-tender, about 12–15 minutes. Using a slotted spoon, remove the potatoes and set aside, keeping the cooking water in the pot.
Cook the green beansIn the same pot of boiling water, add the trimmed green beans and cook for 3–4 minutes, until bright green and tender-crisp. Drain and plunge into a bowl of ice water to stop the cooking. Drain again.
Make the dressingIn a small bowl, whisk together the olive oil, vinegar, garlic, mustard (if using), oregano, salt, and pepper.
Assemble the saladIn a large serving bowl, combine the potatoes, green beans, and sliced red onion. Pour the dressing over the top and toss gently to coat.
Finish & serveSprinkle with chopped parsley and adjust seasoning with more salt, pepper, or vinegar to taste. Serve warm, at room temperature, or chilled.