Roasted Potato Salad

1 ¼ lb. red potatoes, quartered
3 Tbsp. minced shallots
3 Tbsp. white wine vinegar
4 Tbsp. olive oil, divided
1 Tbsp. Dijon mustard
1 tsp. sugar
Salt and pepper to taste
Boil potatoes in salted water over high heat, 8 minutes. Drain, spread on a baking sheet and let cool.
Whisk shallots, vinegar, 2 Tbsp. oil, mustard and sugar in a large bowl. Season with salt and pepper.
In a skillet over high heat, sauté potatoes without stirring, letting them brown, 10 minutes. Stir potatoes and continue to let brown until crisp, 10 minutes. Toss potatoes with vinaigrette until coated.