Fish Roll Sauce - cooking recipe

Ingredients

1/2 cup distilled white vinegar
3 eggs
2 teaspoons vegetable oil
2/3 cup white sugar
1 tablespoon mustard powder
1 tablespoon butter, melted
3 tablespoons all-purpose flour
1 teaspoon salt
1/2 teaspoon ground black pepper
1 cup milk
3 cups water

Preparation

In a medium bowl, mix together eggs, oil, white sugar, mustard, melted butter, flour, salt, and pepper. Mix in milk and water. Set aside.
Heat vinegar in the top of a double boiler over boiling water. Gradually fold egg mixture into the hot vinegar. Cook until the sauce thickens, stirring constantly.