Place all eggs in a medium pot and fill with enough water to cover eggs by one inch.

Place on medium-high heat and let water come to a rolling boil.

Immediately take pot off heat and cover with lid; allow eggs to rest in pot for 10 minutes.

Remove eggs from water and run under cold tap water until cool enough to handle.

Gently peel all eggs, and slice in half longitudinally.

Carefully remove yolks from all halves and place in medium-sized bowl.

Mash yolks with butter, mustard, vinegar and salt until very smooth.

Using a spoon or a small piping bag (AKA a ziplock baggie...), divide mixture evenly into the egg white halves.

Garnish with paprika (or chives, or shallots, or black pepper, or baby smiles, or sprigs of thyme...) sprinkled from a height.