Durkee Famous Sauce  Clone

Ingredients:
- 1/2 cup cold water
- 4 tablespoons cornstarch
- 2/3 cup malt vinegar
- 2 tablespoons salt
- 1/2 cup sugar
- 1 egg
- 4 tablespoons prepared mustard (French's preferred)
- 4 tablespoons butter, cut into tiny bits

Directions:
- Whirl all ingredients in blender on high speed until smooth, about two minutes.
- Transfer to top of double boiler and cook over gently boiling water, stirring often for 12 to 15 minutes or until thickened and smooth.
- Replace mixture back into blender and whirl 30 seconds or until smooth, using high speed.
- Refrigerate in covered container 24 hours before using.
- Keep covered in the refrigerator for up to 3 months.