Cut eggs in half lengthwise. Remove yolks. Set whites aside. Mash yolks with fork.** Stir in sour cream, cheese and 3 tablespoons onions. Refill whites, using 1 heaping tablespoon yolk mixture for each egg half. Garnish with additional onions and pimiento, if desired. Chill to blend flavors.

*To hard-cook: place eggs in single layer in saucepan. Add enough tap water to come at least 1 inch above eggs. Cover. Quickly bring just to boiling. Turn off heat. If necessary, remove pan from burner to prevent further boiling. Let eggs stand, covered, in the hot water, 15 minutes for Large eggs (about 18 minutes for Extra Large eggs and about 12 minutes for Medium). Immediately run cold water over eggs or place them in ice water until completely cooled.

To remove shell: crackle it by tapping gently all over. Roll egg between hands to loosen shell. Then peel, starting at large end. Hold egg under running cold water or dip in bowl of water to help ease off shell.

** To use bag method: place yolks in 1-quart plastic food storage bag. Add sour cream, cheese and 3 tablespoons onions. Press out air. Close bag. Knead until yolk mixture is thoroughly blended. Push yolk mixture toward corner of bag. Snip off about 1/2 inch of bag corner. Squeezing bag gently, fill reserved whites with yolk mixture. Garnish and chill as above.