Deviled Eggs
["12 hard-cooked eggs", "2 tsp. vinegar", "3/4 tsp. salt", "1/8 tsp. pepper", "1 tsp. mustard", "2 Tbsp. melted butter", "3 Tbsp. mayonnaise"]
["Slice eggs lengthwise.", "Remove yolks and mash until lumps are gone.", "Add other ingredients and mix well.", "Spoon into egg whites. Sprinkle with paprika."]
["eggs", "vinegar", "salt", "pepper", "mustard", "butter", "mayonnaise"]