Preheat oven to 350 degrees F. Mix mustard, Roasted Garlic Oil, and potatoes in a large bowl. Place on large baking sheet and scatter the shallots on top. Bake for 20 minutes, or until potatoes are soft.
Slice the hot potatoes into 1/2-inch rounds without worrying if some of the skins slip off. Leave the shallots on them, or around them. Put the potatoes and shallots into the mixing bowl.
In a small bowl combine sour cream, mayonnaise, vinegar, bacon, scallions and remaining 2 Tablespoons mustard. Pour the dressing over the hot potatoes and stir gently to combine. Add salt and pepper to taste.
Cool the potato salad to room temperature, then chill it overnight.