1/4 c. chopped onion
1/3 c. apple cider vinegar
1/2 tsp. prepared mustard
1/3 c. sugar
1 c. oil

Put all of the above into a blender and blend on high until thick. Serve over spinach or garden salad with chopped walnuts, mandarin oranges, olives, tomatoes, etc. Leave in blender until ready to use so you can whip it before you serve it.