Mom'S Potato Salad
["8 medium-size potatoes", "1/4 c. chopped onion", "1/2 c. chopped celery", "4 Tbsp. salad oil", "2 Tbsp. cider vinegar", "1 1/2 tsp. salt", "1/2 tsp. dry mustard", "1/8 tsp. pepper (optional)", "3 boiled eggs, chopped", "2 Tbsp. chopped parsley (optional)", "1/2 c. mayonnaise", "2 Tbsp. milk"]
["Cook diced potatoes 20 to 30 minutes or until tender.", "Drain and spread on towel to cool.", "After cooling, place potatoes in a mixing bowl.", "Sprinkle onion and celery on top of potatoes."]
["potatoes", "onion", "celery", "salad oil", "cider vinegar", "salt", "dry mustard", "pepper", "eggs", "parsley", "mayonnaise", "milk"]