(1)Fill a large wide frying pan or wok with water 4 inches deep and bring to a boil.
(2)Trim the tough ends of the asparagus spears.If desired, remove the "scales"using a vegtable peeler.
(3)Tie the asparagus spears into two bundles.Lower the bundles into the boiling water and cook until just tender, about 2 minutes.
(4)Using a spatula slice, carefully remove the asparagus bundles from the frying pan or wok and immerse in cold water. Drain, then untie the bundles. Pat dry with paper towels. Chill the asparagus in the refrigerator for at least 1 hour.
(5)Combine the vinegar and salt in a bowl and stir with a fork until dissloved. Stir in the mustard. Gradually stir in the oil until it is blended. Add the sour cream or yogurt and pepper to taste.
(6)To serve, place the asaparagus on individual plates and drizzle the dressing on the middle of the spears. Garnish with the fresh raspberries.