Great Grandma'S Salad Dressing - cooking recipe

Ingredients

1/2 cup white sugar
1 tablespoon flour
1 teaspoon dry mustard
1 teaspoon salt
1/2 cup liquid (2/3 vinegar and 1/3 water)
1 tablespoon butter (optional)
1 egg

Preparation

Mix all dry ingredients in a microwave safe bowl, making sure lumps are out of the mustard.
Beat in egg and liquid until smooth.
Microwave on medium for 3 minutes, whisk. Microwave again for 2 minutes, whisk.
When dressing is the consistency you like (don't overcook it), you can add the optional butter, but I no longer do.
chill and use with tuna salad or potato salad.