Mayonnaise Potato Salad
["2 lb. potatoes", "1 1/2 tsp. salt", "1/2 tsp. pepper", "2 Tbsp. vinegar", "1 onion, diced", "1 c. celery, chopped", "1/2 c. mayonnaise (if dry, add more)", "1 Tbsp. Dijon mustard"]
["Boil, peel and dice potatoes.", "Sprinkle with salt and pepper. Add vinegar, onion and celery.", "Mix mayonnaise and mustard.", "Pour over potatoes and mix.", "Chill 2 hours.", "Serve cold."]
["potatoes", "salt", "pepper", "vinegar", "onion", "celery", "mayonnaise", "mustard"]