Using the insides of the red onion, finely dice, 1/4 pound. Place the bacon grease in a saucepan over medium-high heat. Add the onions and saute until the onions start to blacken. While the onions are caramelizing, in a mixing bowl place the water, honey and red wine vinegar. Using a wire whisk, mix the ingredients well. Add the cornstarch and whisk well. After the onions have caramelized, add the Dijon mustard to the onions and stir together with a rubber spatula. Add the water, vinegar, pepper, honey and cornstarch to the mustard and onions and mix. Continue stirring until mix thickens and comes to a boil. Remove from heat and store in refrigerator until needed. Makes 1 quart. Note: To reheat use a double boiler. I put the Tabasco on the ingredient list if you like it. In different parts of the country Bennigan's omits this ingredient.