Beat egg yolks until lemon color, then add next 4 ingredients. Beat in 1/2 cup salad oil very slowly until mixture begins to thicken. Mix vinegar and lemon juice together and alternate adding, drop by drop, with second 1/4 cup of oil. Add the onion, garlic, celery seed, and Tabasco, stirring. Thin dressing, if necessary, with light cream. Makes 1 1/2 cups.