Step 1

Cook the pasta according to package directions. Drain.

Step 2

While the pasta is cooking, place the eggs in a small saucepan. Cover with water and bring to a boil. Remove from heat, cover and let stand for 12 minutes. Run under cold water to cool.

Step 3

In a large bowl, whisk together the sour cream, mayonnaise, mustard, lemon juice, and 1/4 teaspoon each salt and pepper. Add the pasta and toss to coat.

Step 4

Peel the eggs. Using the large holes on a box grater, grate one egg and 3 egg whites (discard the yolks). Fold the eggs into the pasta mixture along with the celery, bell pepper, pimiento, and scallions.