Boil eggs: Place eggs in single layer in saucepan. Cover with cold water by 1 inch. Add pinch of salt. Bring to rolling boil over high heat.
Cook: Once boiling, immediately remove from heat, cover with lid, and let sit exactly 12 minutes.
Ice bath: Prepare bowl of ice water. After 12 minutes, transfer eggs to ice bath using slotted spoon. Let sit 5 minutes minimum.
Peel: Tap eggs all over to crack shell. Roll gently on counter and peel starting from wider end. Rinse under cold water and pat dry.
Chop eggs: Chop eggs into small, uniform ¼-inch pieces. Don't mash—aim for distinct pieces throughout.
Make dressing: Whisk together mayonnaise, sour cream, Dijon mustard, lemon juice, celery salt, onion powder, white pepper, and salt until smooth.
Combine: Place chopped eggs in large bowl. Add mayonnaise mixture and gently fold together until evenly coated. Don't overmix.
Add herbs: Fold in chopped chives and dill gently until evenly distributed.
Season: Taste and adjust seasoning. Add more salt, pepper, or lemon juice as needed. Add more mayo if too thick.
Chill: Cover with plastic wrap and refrigerate minimum 1 hour before serving to allow flavors to meld.
Garnish: Before serving, stir gently. Sprinkle with paprika and garnish with fresh dill if desired.
Serve: Serve on croissants, bread, crackers, or lettuce cups.