Deviled Eggs
["4 hard-cooked eggs", "1/4 tsp. salt", "1/2 tsp. dry mustard", "1/8 tsp. pepper", "1 tsp. vinegar", "1 Tbsp. melted butter"]
["Cook eggs; remove shells and cut each in half lengthwise. Remove yolks.", "Mix yolks with rest of ingredients.", "Fill each half white of egg with mixture."]
["eggs", "salt", "dry mustard", "pepper", "vinegar", "butter"]