In a bowl, combine the livers and milk to cover. Soak, refrigerated, for at least 8 hours or overnight. Drain well.

In a large, heavy skillet, heat the oil over medium-high heat. Add the livers, onions, thyme, bay leaves, 1 teaspoon of the salt, and the white pepper. Cook, stirring occasionally, until the livers are just slightly pink and the onions are soft, about 5 minutes. Carefully add the brandy and cook until the liquid is evaporated and the livers are cooked through but still tender. Remove from the heat and spread on a large plate to cool. Transfer to a food processor. Add the cream cheese and butter, and process on high speed until smooth. Add the remaining 1/2 teaspoon of salt and pulse to blend.

Line a 5-cup loaf pan (8 1/2 by 4 1/2 by 3-inches) with plastic wrap, leaving an overhang of several inches. Spoon the mixture into the terrine, smoothing out with a rubber spatula. Wrap the terrine with the overhanging wrap and chill until firm, at least 8 hours.

To serve, unwrap the terrine, lift from the mold, and slice with a sharp knife. Place 1 slice on each plate with a heaping tablespoon of the mustard sauce and serve with the croutons or crackers.

In a blender or food processor, combine the egg yolk, soy sauce, Creole mustard, Worcestershire, salt, and pepper, and process for 20 seconds on high speed.

With the machine running, add the oil through the feed tube in a steady stream and process until it is smooth and thick.

Adjust the seasoning, to taste.

*RAW EGG WARNING

Food Network Kitchens suggest caution in consuming raw and lightly-cooked eggs due to the slight risk of Salmonella or other food-borne illness. To reduce this risk, we recommend you use only fresh, properly-refrigerated, clean, grade A or AA eggs with intact shells, and avoid contact between the yolks or whites and the shell.