Wash the red potatoes and slice into 1-inch pieces. Place the sliced potatoes in an 8 x 8-inch baking dish.
Add the vegetable oil, a ½ teaspoon of the salt and a ½ teaspoon of the pepper. Toss to coat the potatoes.
Place in the oven and roast the potatoes for 20-25 minutes, just until they're tender and beginning to brown on the edges. Remove the pan from the oven and allow the potatoes to cool to room temperature.
Make the dressing:
While the potatoes roast, place the parsley, tarragon, anchovy fillets and garlic into the bowl of a food processor or mini chopper. Pulse until everything is finely minced. Scrape the mixture into a large bowl.
Add the mayonnaise, buttermilk and chopped scallions to the bowl. Whisk until the mixture is smooth, and all ingredients are combined. Add the remaining ½ teaspoons of the salt and the pepper and whisk again.
Finish the salad:
Add the cooled, roasted potatoes to the dressing and gently toss to coat them completely.
Transfer the potato salad to a serving bowl and garnish with the snipped chives.
The salad can be served immediately or it can be chilled first in the refrigerator. Store any leftovers in the fridge for up to 3 days. Makes about 7 cups.
Notes
Look for fresh parsley and tarragon in the produce section with other fresh herbs. Or, get them from your garden if you grow them!
Not everyone is a fan of anchovies, but don't worry: they don't make this salad taste fishy. They just add a little salty umami flavor that nicely boosts the fresh herbs and tangy buttermilk in the dressing.