Mix 6 tablespoons of olive oil, the garlic, salt, pepper and herbs.
Add potatoes and toss.
Spread out onto a baking sheet and bake for 55 minutes, stirring occasionally. When potatoes are golden brown remove the pan from the oven and let cool. When potatoes are cool, place them in a bowl and scrape the pan drippings into a measuring cup.
Add enough oil to the drippings to measure 6 tablespoons of oil.
Whisk the vinegar and mustard in a small bowl. Gradually add the oil and then mix in the shallots.
Pour the dressing over the potatoes and combine. Season with salt and pepper, if needed.