Preheat oven to 350 degrees Fahrenheit. Cut sweet potatoes into cubes and toss with oil, salt, and pepper. (Don’t overspice the sweet potatoes because they will be dressed after they are roasted.)
Roast flat on baking sheet for 25 minutes or until potatoes are cooked through. Stir potatoes every few minutes so they bake evenly.
Whisk dressing ingredients together. Warm dressing and pour over hot potatoes just before serving. (You can serve the extra dressing in a cruet on the side.)