This simple side riffs on the traditional pub combination of fries and malt vinegar. They are roasted to perfection, which gives a delicious crispy exterior.
Preheat oven to 400°F.
Combine potatoes, oil, 1 tablespoon vinegar, 1/2 teaspoon salt and pepper in a medium bowl and toss to coat. Spread in a single layer on a large rimmed baking sheet. Roast, stirring once, until golden brown and tender, 35 to 45 minutes.
Return the potatoes to the bowl and add the remaining 1 tablespoon vinegar, pinch of salt and herbs, if using; toss to combine.