Recipe(tried): Spicy French Dressing (sweet and tangy but not creamy)

Here is my simple recipe for

Spicy French Dressing
(sweet and tangy; but not creamy)
Makes about 2 cups

1/2 cup sugar
1/2 cup cider vinegar
1 T. flour
1 tsp. salt
1 tsp Worcestershire
dash onion powder
dash garlic
2 T. olive oil
1/4 cup ketchup
1 tsp celery seeds (optional)

In a small pan, stir together sugar, vinegar, and flour. Cook over medium heat, stirring, until bubbly and thick. Remove from heat - add salt, Worcestershire, onion and garlic; whirl until smooth. While stirring, slowly pour in oil in a thin, steady stream, whirling until blended.
Stir in ketsup and celery seeds. Store in glass container in refrigerator for up to a month.