Poppy Seed Dressing

In a small saucepan, combine the sugar, mustard, salt, vinegar, and onion.

Stir over moderate heat for 3 minutes, or until the sugar dissolves.

Remove from the heat.

Using a wire whisk or rotary beater, gradually beat the oil into the mixture and continue beating until the mixture thickens.

Stir in the poppy seeds.

Store in the refrigerator and beat again just before serving.