Durkee Famous Sauce Clone - cooking recipe

Ingredients

1/2 cup cold water
4 tablespoons cornstarch
1/2 cup balsamic vinegar, plus
2 tablespoons balsamic vinegar
1 tablespoon salt, plus
2 teaspoons salt
1/2 cup sugar
1 egg
4 tablespoons prepared mustard
4 tablespoons unsalted butter

Preparation

Put all ingredients, except for the butter, into your blender.
Blend on high speed about 2 minutes or until mixture is smooth.
Pour into top pan of a double boiler.
Cook over gently boiling water.
As sauce begins to heat, add butter, stirring often to incorporate.
Cook for 12-15 minutes (stirring often) or until sauce becomes thick and smooth.
Remove from heat and allow to cool.
Cooled sauce may be run thru blender, again, on high speed for about a minute till smooth.
Refrigerate sauce in covered container for several hours before using.
Will keep, refrigerated, about 1 month.