1 sm. onion, cut up
1 c. mayonnaise or salad dressing
1/3 c. salad oil
1/4 c. catsup
2 tbsp. sugar
2 tbsp. vinegar
1 tsp. mustard
1/2 tsp. salt
1/2 tsp. paprika
1/4 tsp. celery seed
Dash of pepper
1 c. bleu cheese, crumbled (4 oz.)

Put all ingredients, except bleu cheese, into blender. Cover and blend until smooth. Stir in the bleu cheese. Cover and chill. Serve over tossed salad.