Onion Salad Dressing 3   Ingredients: 1/4 cup of vinegar. 3/4 cup of sugar. 1/2 teaspoon of dry mustard. 1/4 whole onion, or green onions. 1/4 teaspoon of salt. 1 cup of corn oil. 1/2 teaspoon of celery seed. Directions: Blend in blender for 10 minutes. Download This Recipe