1. Preheat oven to 400°. Toss potatoes with 2 Tbsp. olive oil; place in a single layer in a jelly-roll pan. Bake 30 to 35 minutes or until golden.
2. Meanwhile, whisk together vinegar and next 4 ingredients in a large bowl. Add shallot; gradually whisk in vegetable oil, crème fraîche, and remaining 3 Tbsp. olive oil, whisking until well blended. Remove potatoes from oven, and gently toss with vinegar mixture and chives. Season with kosher salt and pepper to taste.